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Geng DQ, Wang XL, Lyu XY, Raikhel AS, Zou Z. Ecdysone-controlled nuclear receptor ERR regulates metabolic homeostasis in the disease vector mosquito Aedes aegypti. PLoS Genet 2024; 20:e1011196. [PMID: 38466721 PMCID: PMC10957079 DOI: 10.1371/journal.pgen.1011196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 03/21/2024] [Accepted: 02/20/2024] [Indexed: 03/13/2024] Open
Abstract
Hematophagous mosquitoes require vertebrate blood for their reproductive cycles, making them effective vectors for transmitting dangerous human diseases. Thus, high-intensity metabolism is needed to support reproductive events of female mosquitoes. However, the regulatory mechanism linking metabolism and reproduction in mosquitoes remains largely unclear. In this study, we found that the expression of estrogen-related receptor (ERR), a nuclear receptor, is activated by the direct binding of 20-hydroxyecdysone (20E) and ecdysone receptor (EcR) to the ecdysone response element (EcRE) in the ERR promoter region during the gonadotropic cycle of Aedes aegypti (named AaERR). RNA interference (RNAi) of AaERR in female mosquitoes led to delayed development of ovaries. mRNA abundance of genes encoding key enzymes involved in carbohydrate metabolism (CM)-glucose-6-phosphate isomerase (GPI) and pyruvate kinase (PYK)-was significantly decreased in AaERR knockdown mosquitoes, while the levels of metabolites, such as glycogen, glucose, and trehalose, were elevated. The expression of fatty acid synthase (FAS) was notably downregulated, and lipid accumulation was reduced in response to AaERR depletion. Dual luciferase reporter assays and electrophoretic mobility shift assays (EMSA) determined that AaERR directly activated the expression of metabolic genes, such as GPI, PYK, and FAS, by binding to the corresponding AaERR-responsive motif in the promoter region of these genes. Our results have revealed an important role of AaERR in the regulation of metabolism during mosquito reproduction and offer a novel target for mosquito control.
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Affiliation(s)
- Dan-Qian Geng
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Xue-Li Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Xiang-Yang Lyu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Alexander S. Raikhel
- Department of Entomology, University of California, Riverside, California, United States of America
- Institute for Integrative Genome Biology, University of California, Riverside, California, United States of America
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
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2
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Sun X, Wang X, Shi K, Lyu X, Sun J, Raikhel AS, Zou Z. Leucine aminopeptidase1 controls egg deposition and hatchability in male Aedes aegypti mosquitoes. Nat Commun 2024; 15:106. [PMID: 38168045 PMCID: PMC10762072 DOI: 10.1038/s41467-023-44444-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 12/13/2023] [Indexed: 01/05/2024] Open
Abstract
Aedes aegypti are vectors for several arboviruses infecting hundreds of millions of people annually. Controlling mosquito populations by regulating their reproduction is a potential strategy to minimize viral transmission in the absence of effective antiviral therapies or vaccines. Here, we demonstrate that leucine aminopeptidase1 (LAP1), detected by a SWATH-MS-based proteomic screen of female spermathecae, is a crucial determinant in mosquito population expansion. Mitochondrial defects and aberrant autophagy of sperm in LAP1 mutant males (LAP1-/-), prepared using CRISPR/Cas9 system, result in a reduction of reproduction in wild-type females that mated with them. The fitness of LAP1-/- males is strong enough to efficiently transmit genetic changes to mosquito populations through a low number of hatchable offspring. Thus, LAP1-/- males represent an opportunity to suppress mosquito populations and further studies should be undertaken to characterize LAP1's suitability for gene drive usage.
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Affiliation(s)
- Xiaomei Sun
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xueli Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Kai Shi
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiangyang Lyu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jian Sun
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Alexander S Raikhel
- Department of Entomology, University of California, Riverside, CA, 92521, USA
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China.
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Ling L, Raikhel AS. Amino acid-dependent regulation of insulin-like peptide signaling is mediated by TOR and GATA factors in the disease vector mosquito Aedes aegypti. Proc Natl Acad Sci U S A 2023; 120:e2303234120. [PMID: 37579141 PMCID: PMC10450652 DOI: 10.1073/pnas.2303234120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 07/25/2023] [Indexed: 08/16/2023] Open
Abstract
Aedes aegypti female mosquitoes require vertebrate blood for their egg production and consequently they become vectors of devastating human diseases. Amino acids (AAs) and nutrients originating from a blood meal activate vitellogenesis and fuel embryo development of anautogenous mosquitoes. Insulin-like peptides (ILPs) are indispensable in reproducing female mosquitoes, regulating glycogen and lipid metabolism, and other essential functions. However, how ILPs coordinate their action in response to the AA influx in mosquito reproduction was unknown. We report here that the AA/Target of Rapamycin (TOR) signaling pathway regulates ILPs through GATA transcription factors (TFs). AA infusion combined with RNA-interference TOR silencing of revealed their differential action on ILPs, elevating circulating levels of several ILPs but inhibiting others, in the female mosquito. Experiments involving isoform-specific CRISPR-Cas9 genomic editing and chromatin immunoprecipitation assays showed that the expression of ilp4, ilp6, and ilp7 genes was inhibited by the GATA repressor (GATAr) isoform in response to low AA-TOR signaling, while the expression of ilp1, ilp2, ilp3, ilp5, and ilp8 genes was activated by the GATA activator isoform after a blood meal in response to the increased AA-TOR signaling. FoxO, a downstream TF in the insulin pathway, was involved in the TOR-GATAr-mediated repression of ilp4, ilp6, and ilp7 genes. This work uncovered how AA/TOR signaling controls the ILP pathway in modulation of metabolic requirements of reproducing female mosquitoes.
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Affiliation(s)
- Lin Ling
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing210096, China
| | - Alexander S. Raikhel
- Department of Entomology, University of California, Riverside, CA92521
- Institute of Integrative Genome Biology, University of California, Riverside, CA92521
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Wang M, Wang Y, Chang M, Wang X, Shi Z, Raikhel AS, Zou Z. Ecdysone signaling mediates the trade-off between immunity and reproduction via suppression of amyloids in the mosquito Aedes aegypti. PLoS Pathog 2022; 18:e1010837. [PMID: 36137163 PMCID: PMC9531809 DOI: 10.1371/journal.ppat.1010837] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 10/04/2022] [Accepted: 08/29/2022] [Indexed: 11/18/2022] Open
Abstract
The balance between immunity and reproduction is essential for many key physiological functions. We report that to maintain an optimal fertility, 20-hydroxyecdysone (20E) and the ecdysone receptor (EcR) downregulate the immune deficiency (IMD) pathway during the post blood meal phase (PBM) of the Aedes aegypti reproductive cycle. RNA interference-mediated depletion of EcR elicited an increased expression of the IMD pathway components, and these mosquitoes were more resistant to infection by Gram-negative bacteria. Moreover, 20E and EcR recruit Pirk-like, the mosquito ortholog of Drosophila melanogaster Pirk. CRISPR-Cas9 knockout of Pirk-like has shown that it represses the IMD pathway by interfering with IMD-mediated formation of amyloid aggregates. 20E and EcR disruption of the amyloid formation is pivotal for maintaining normal yolk protein production and fertility. Additionally, 20E and its receptor EcR directly induce Pirk-like to interfere with cRHIM-mediated formation of amyloid. Our study highlights the vital role of 20E in governing the trade-off between immunity and reproduction. Pirk-like might be a potential target for new methods to control mosquito reproduction and pathogen transmission.
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Affiliation(s)
- Mao Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, People’s Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Yanhong Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, People’s Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Mengmeng Chang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, People’s Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Xueli Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, People’s Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Zuokun Shi
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, People’s Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Alexander S. Raikhel
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, California, United States of America
- * E-mail: (ASR); (ZZ)
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, People’s Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
- * E-mail: (ASR); (ZZ)
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He YZ, Ding Y, Wang X, Zou Z, Raikhel AS. E93 confers steroid hormone responsiveness of digestive enzymes to promote blood meal digestion in the midgut of the mosquito Aedes aegypti. Insect Biochem Mol Biol 2021; 134:103580. [PMID: 33901693 PMCID: PMC8947147 DOI: 10.1016/j.ibmb.2021.103580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/19/2021] [Accepted: 04/19/2021] [Indexed: 06/12/2023]
Abstract
Anautogenous female mosquitoes obtain the nutrients needed for egg development from vertebrate blood, and consequently they transmit numerous pathogens of devastating human diseases. Digestion of blood proteins into amino acids that are used for energy production, egg maturation and replenishment of maternal reserves is an essential part of the female mosquito reproductive cycle. However, the regulatory mechanisms underlying this process remain largely unknown. Here, we report that the transcription factor E93 is a critical factor promoting blood meal digestion in adult females of the major arboviral vector Aedes aegypti in response to the steroid hormone 20-hydroxyecdysone (20E). E93 was upregulated in the female mosquito midgut after a blood meal, and RNA interference (RNAi)-mediated knockdown of E93 inhibited midgut blood digestion. E93 RNAi depletion repressed late trypsin (LT), serine protease I (SPI), SPVI and SPVII, and activated early trypsin (ET) expression in the female mosquito midgut after a blood meal. Injection of 20E activated E93, LT, SPI, SPVI and SPVII, and repressed ET expression, whereas RNAi knockdown of the ecdysone receptor (EcR) repressed E93, LT, SPI, SPVI and SPVII, and activated ET expression in the midgut. Furthermore, E93 depletion resulted in a complete loss of 20E responsiveness of LT, SPVI and SPVII. Our findings reveal important mechanisms regulating blood meal digestion in disease-transmitting mosquitoes.
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Affiliation(s)
- Ya-Zhou He
- Department of Entomology, University of California, Riverside, CA, 92521, USA; Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
| | - Yike Ding
- Department of Entomology, University of California, Riverside, CA, 92521, USA; Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
| | - Xueli Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Alexander S Raikhel
- Department of Entomology, University of California, Riverside, CA, 92521, USA; Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA.
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6
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Wang X, Ding Y, Lu X, Geng D, Li S, Raikhel AS, Zou Z. The ecdysone-induced protein 93 is a key factor regulating gonadotrophic cycles in the adult female mosquito Aedes aegypti. Proc Natl Acad Sci U S A 2021; 118:e2021910118. [PMID: 33593917 PMCID: PMC7923369 DOI: 10.1073/pnas.2021910118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Repeated blood feedings are required for adult female mosquitoes to maintain their gonadotrophic cycles, enabling them to be important pathogen carriers of human diseases. Elucidating the molecular mechanism underlying developmental switches between these mosquito gonadotrophic cycles will provide valuable insight into mosquito reproduction and could aid in the identification of targets to disrupt these cycles, thereby reducing disease transmission. We report here that the transcription factor ecdysone-induced protein 93 (E93), previously implicated in insect metamorphic transitions, plays a key role in determining the gonadotrophic cyclicity in adult females of the major arboviral vector Aedes aegypti Expression of the E93 gene in mosquitoes is down-regulated by juvenile hormone (JH) and up-regulated by 20-hydroxyecdysone (20E). We find that E93 controls Hormone Receptor 3 (HR3), the transcription factor linked to the termination of reproductive cycles. Moreover, knockdown of E93 expression via RNAi impaired fat body autophagy, suggesting that E93 governs autophagy-induced termination of vitellogenesis. E93 RNAi silencing prior to the first gonadotrophic cycle affected normal progression of the second cycle. Finally, transcriptomic analysis showed a considerable E93-dependent decline in the expression of genes involved in translation and metabolism at the end of a reproductive cycle. In conclusion, our data demonstrate that E93 acts as a crucial factor in regulating reproductive cycle switches in adult female mosquitoes.
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Affiliation(s)
- Xueli Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
| | - Yike Ding
- Department of Entomology, University of California, Riverside, CA 92521
- Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Xiangyang Lu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
| | - Danqian Geng
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
| | - Shan Li
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
| | - Alexander S Raikhel
- Department of Entomology, University of California, Riverside, CA 92521;
- Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China;
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
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Chang MM, Wang YH, Yang QT, Wang XL, Wang M, Raikhel AS, Zou Z. Regulation of antimicrobial peptides by juvenile hormone and its receptor, Methoprene-tolerant, in the mosquito Aedes aegypti. Insect Biochem Mol Biol 2021; 128:103509. [PMID: 33264664 DOI: 10.1016/j.ibmb.2020.103509] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 11/09/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
The trade-off between reproduction and immunity has been established for a number of insect species. However, the regulatory mechanisms governing this event is not well understood. In the mosquito Aedes aegypti, the vector of dangerous human arboviral diseases, juvenile hormone (JH) is required for the female post-eclosion development and reproductive maturation. In this study, we have revealed the JH negative effect on the expression of immunity-related genes, such as antimicrobial peptides (AMPs), during the post-eclosion phase of the female mosquito gonadotrophic reproductive cycle. Mosquitoes treated with JH became more sensitive to microbial infection. Mosquitoes subjected to the RNA interference knockdown (RNAi) of the JH receptor, Methoprene-tolerant (Met), showed increased expression of several AMP genes. Met binds to the E-box-like recognition motifs in the regulatory region of the diptericin (Dpt) gene, indicating that JH can suppress the Dpt gene expression through its receptor Met. Hence, JH is involved in the modulation of immune responses during the post-eclosion phase of reproduction. The RNAi knockdown of the peptidoglycan recognition protein (PGRP-LC) led to a significant reduction of the Dpt transcript level, indicating the PGRP-LC activating role on this AMP gene. Thus, Dpt appeared to be under the dual regulation of both the JH and the immune deficiency (IMD) signaling pathways. Our study provides a better understanding of how JH regulates insect immunity in adult mosquitoes.
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Affiliation(s)
- Meng-Meng Chang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yan-Hong Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qing-Tai Yang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xue-Li Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mao Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Alexander S Raikhel
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China; Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, Huzhou University, Huzhou, 311300, China.
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Abstract
The yellow fever mosquito Aedes aegypti is an obligatory blood feeder and a major arboviral disease vector, evoking severe public health concerns worldwide. In adult female mosquitoes, the gut is critical for blood digestion and pathogen entry. We aimed for a systematic exploration of microRNA expression dynamics in the gut during the gonadotrophic cycle. Small RNA libraries were constructed from female mosquito gut tissues at five time points. Unsupervised hierarchical clustering revealed three expression clusters (early, mid and late) peaking at sequential time points - 24, 48 and 72 h posteclosion. Differentially expressed miRNAs were identified at 24 h post-blood meal (PBM). Depletions of Methoprene-tolerant [Met; the juvenile hormone (JH) receptor] and Ecdysone receptor [EcR; the receptor to 20-hydroxyecdysone (20E)] were performed using dsRNA to these genes to investigate impacts on microRNA expressions. Our results suggest that Met-mediated signalling downregulates miRNA expression from the early cluster and upregulates that from the late cluster. EcR signalling either up- or downregulated miRNA levels at 24 h PBM, indicating a differential effect of this receptor in miRNA gene expression. Furthermore, miR-281, which is the most abundant miRNA in the gut tissue, is induced and repressed by Met- and EcR-mediated signalling, respectively. Systematic depletion using synthetic antagomir and phenotype examinations indicate that miR-281 is obligatory for the normal progression of blood digestion, ovarian development and reproduction. Collectively, this study unveils expression dynamics of microRNAs in the female gut tissue during the gonadotrophic cycle and demonstrates that they are affected by JH and 20E signalling.
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Affiliation(s)
- Xiufeng Zhang
- Department of Entomology and Institute of Integrative Genome Biology, University of California, Riverside, CA, USA
| | - Alexander S Raikhel
- Department of Entomology and Institute of Integrative Genome Biology, University of California, Riverside, CA, USA
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Saha TT, Roy S, Pei G, Dou W, Zou Z, Raikhel AS. Synergistic action of the transcription factors Krüppel homolog 1 and Hairy in juvenile hormone/Methoprene-tolerant-mediated gene-repression in the mosquito Aedes aegypti. PLoS Genet 2019; 15:e1008443. [PMID: 31661489 PMCID: PMC6818763 DOI: 10.1371/journal.pgen.1008443] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 09/23/2019] [Indexed: 12/31/2022] Open
Abstract
Arthropod-specific juvenile hormones control numerous essential functions in development and reproduction. In the dengue-fever mosquito Aedes aegypti, in addition to its role in immature stages, juvenile hormone III (JH) governs post-eclosion (PE) development in adult females, a phase required for competence acquisition for blood feeding and subsequent egg maturation. During PE, JH through its receptor Methoprene-tolerant (Met) regulate the expression of many genes, causing either activation or repression. Met-mediated gene repression is indirect, requiring involvement of intermediate repressors. Hairy, which functions downstream of Met in the JH gene-repression hierarchy, is one such factor. Krüppel-homolog 1, a zinc-finger transcriptional factor, is directly regulated by Met and has been implicated in both activation and repression of JH-regulated genes. However, the interaction between Hairy and Kr-h1 in the JH-repression hierarchy is not well understood. Our RNAseq-based transcriptomic analysis of the Kr-h1-depleted mosquito fat body revealed that 92% of Kr-h1 repressed genes are also repressed by Met, supporting the existence of a hierarchy between Met and Kr-h1 as previously demonstrated in various insects. Notably, 130 genes are co-repressed by both Kr-h1 and Hairy, indicating regulatory complexity of the JH-mediated PE gene repression. A mosquito Kr-h1 binding site in genes co-regulated by this factor and Hairy was identified computationally. Moreover, this was validated using electrophoretic mobility shift assays. A complete phenocopy of the effect of Met RNAi depletion on target genes could only be observed after Kr-h1 and Hairy double RNAi knockdown, suggesting a synergistic action between these two factors in target gene repression. This was confirmed using a cell-culture-based luciferase reporter assay. Taken together, our results indicate that Hairy and Kr-h1 not only function as intermediate downstream factors, but also act together in a synergistic fashion in the JH/Met gene repression hierarchy. Juvenile hormone (JH) plays an essential role in preparing Aedes aegypti female mosquitoes for blood feeding, egg development, and pathogen transmission. JH acting through its receptor Methoprene-tolerant (Met) regulates the expression of large gene cohorts. JH mediated gene repression, unlike activation that is directly mediated by Met, is indirect and requires intermediate transcriptional repressors Hairy and Krüppel-homolog 1 (Kr-h1). Here, we demonstrate that Hairy and Kr-h1 can act synergistically in the JH-Met gene repression pathway in Aedes female mosquitoes. These interact directly with regulatory regions of the genes that have both Hairy and Kr-h1 binding sites. Thus, this study has significantly advanced our understanding of the complexity of the JH-mediated gene expression pathway. This research yields valuable information about the JH control of reproductive development of the mosquito A. aegypti, one of the most important vectors of human diseases.
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Affiliation(s)
- Tusar T. Saha
- Department of Entomology and Institute of Integrative Biology, University of California, Riverside, California, United States of America
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, K. K. Birla Goa Campus, Goa, India
| | - Sourav Roy
- Department of Entomology and Institute of Integrative Biology, University of California, Riverside, California, United States of America
- Department of Biological Sciences, University of Texas El Paso, Texas
| | - Gaofeng Pei
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wei Dou
- Department of Entomology and Institute of Integrative Biology, University of California, Riverside, California, United States of America
- College of Plant Protection, Southwest University, Chongqing, China
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Alexander S. Raikhel
- Department of Entomology and Institute of Integrative Biology, University of California, Riverside, California, United States of America
- * E-mail:
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10
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Matthews BJ, Dudchenko O, Kingan SB, Koren S, Antoshechkin I, Crawford JE, Glassford WJ, Herre M, Redmond SN, Rose NH, Weedall GD, Wu Y, Batra SS, Brito-Sierra CA, Buckingham SD, Campbell CL, Chan S, Cox E, Evans BR, Fansiri T, Filipović I, Fontaine A, Gloria-Soria A, Hall R, Joardar VS, Jones AK, Kay RGG, Kodali VK, Lee J, Lycett GJ, Mitchell SN, Muehling J, Murphy MR, Omer AD, Partridge FA, Peluso P, Aiden AP, Ramasamy V, Rašić G, Roy S, Saavedra-Rodriguez K, Sharan S, Sharma A, Smith ML, Turner J, Weakley AM, Zhao Z, Akbari OS, Black WC, Cao H, Darby AC, Hill CA, Johnston JS, Murphy TD, Raikhel AS, Sattelle DB, Sharakhov IV, White BJ, Zhao L, Aiden EL, Mann RS, Lambrechts L, Powell JR, Sharakhova MV, Tu Z, Robertson HM, McBride CS, Hastie AR, Korlach J, Neafsey DE, Phillippy AM, Vosshall LB. Improved reference genome of Aedes aegypti informs arbovirus vector control. Nature 2018; 563:501-507. [PMID: 30429615 PMCID: PMC6421076 DOI: 10.1038/s41586-018-0692-z] [Citation(s) in RCA: 306] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 10/05/2018] [Indexed: 11/10/2022]
Abstract
Female Aedes aegypti mosquitoes infect more than 400 million people each year with dangerous viral pathogens including dengue, yellow fever, Zika and chikungunya. Progress in understanding the biology of mosquitoes and developing the tools to fight them has been slowed by the lack of a high-quality genome assembly. Here we combine diverse technologies to produce the markedly improved, fully re-annotated AaegL5 genome assembly, and demonstrate how it accelerates mosquito science. We anchored physical and cytogenetic maps, doubled the number of known chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites, provided further insight into the size and composition of the sex-determining M locus, and revealed copy-number variation among glutathione S-transferase genes that are important for insecticide resistance. Using high-resolution quantitative trait locus and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly disease vector. An improved, fully re-annotated Aedes aegypti genome assembly (AaegL5) provides insights into the sex-determining M locus, chemosensory systems that help mosquitoes to hunt humans and loci involved in insecticide resistance and will help to generate intervention strategies to fight this deadly disease vector.
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Affiliation(s)
- Benjamin J Matthews
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY, USA. .,Howard Hughes Medical Institute, New York, NY, USA. .,Kavli Neural Systems Institute, New York, NY, USA.
| | - Olga Dudchenko
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Computer Science, Rice University, Houston, TX, USA.,Center for Theoretical and Biological Physics, Rice University, Houston, TX, USA
| | | | - Sergey Koren
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Igor Antoshechkin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | | | - William J Glassford
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Margaret Herre
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY, USA.,Kavli Neural Systems Institute, New York, NY, USA
| | - Seth N Redmond
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.,Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Noah H Rose
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.,Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Gareth D Weedall
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, UK.,Liverpool John Moores University, Liverpool, UK
| | - Yang Wu
- Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China.,Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, USA
| | - Sanjit S Batra
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Computer Science, Rice University, Houston, TX, USA
| | - Carlos A Brito-Sierra
- Department of Entomology, Purdue University, West Lafayette, IN, USA.,Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, USA
| | - Steven D Buckingham
- Centre for Respiratory Biology, UCL Respiratory, University College London, London, UK
| | - Corey L Campbell
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Saki Chan
- Bionano Genomics, San Diego, CA, USA
| | - Eric Cox
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Benjamin R Evans
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
| | - Thanyalak Fansiri
- Vector Biology and Control Section, Department of Entomology, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Igor Filipović
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Albin Fontaine
- Insect-Virus Interactions Group, Department of Genomes and Genetics, Institut Pasteur, Paris, France.,Unité de Parasitologie et Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Marseille, France.,Centre National de la Recherche Scientifique, Unité Mixte de Recherche 2000, Paris, France.,Aix Marseille Université, IRD, AP-HM, SSA, UMR Vecteurs - Infections Tropicales et Méditerranéennes (VITROME), IHU - Méditerranée Infection, Marseille, France
| | - Andrea Gloria-Soria
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA.,The Connecticut Agricultural Experiment Station, New Haven, CT, USA
| | | | - Vinita S Joardar
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Andrew K Jones
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
| | - Raissa G G Kay
- Department of Entomology, University of California Riverside, Riverside, CA, USA
| | - Vamsi K Kodali
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Joyce Lee
- Bionano Genomics, San Diego, CA, USA
| | - Gareth J Lycett
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | | | - Michael R Murphy
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Arina D Omer
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Computer Science, Rice University, Houston, TX, USA
| | - Frederick A Partridge
- Centre for Respiratory Biology, UCL Respiratory, University College London, London, UK
| | | | - Aviva Presser Aiden
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Bioengineering, Rice University, Houston, TX, USA.,Department of Pediatrics, Texas Children's Hospital, Houston, TX, USA
| | - Vidya Ramasamy
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
| | - Gordana Rašić
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Sourav Roy
- Department of Entomology, Center for Disease Vector Research and Institute for Integrative Genome Biology, University of California, Riverside, CA, USA
| | - Karla Saavedra-Rodriguez
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Shruti Sharan
- Department of Entomology, Purdue University, West Lafayette, IN, USA.,Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, USA
| | - Atashi Sharma
- Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, USA.,Department of Entomology, Virginia Tech, Blacksburg, VA, USA
| | | | - Joe Turner
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | | | - Zhilei Zhao
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.,Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Omar S Akbari
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA.,Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA, USA
| | - William C Black
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Han Cao
- Bionano Genomics, San Diego, CA, USA
| | - Alistair C Darby
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Catherine A Hill
- Department of Entomology, Purdue University, West Lafayette, IN, USA.,Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, USA
| | - J Spencer Johnston
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Terence D Murphy
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Alexander S Raikhel
- Department of Entomology, Center for Disease Vector Research and Institute for Integrative Genome Biology, University of California, Riverside, CA, USA
| | - David B Sattelle
- Centre for Respiratory Biology, UCL Respiratory, University College London, London, UK
| | - Igor V Sharakhov
- Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, USA.,Department of Entomology, Virginia Tech, Blacksburg, VA, USA.,Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, Tomsk, Russia
| | | | - Li Zhao
- Laboratory of Evolutionary Genetics and Genomics, The Rockefeller University, New York, NY, USA
| | - Erez Lieberman Aiden
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Computer Science, Rice University, Houston, TX, USA.,Center for Theoretical and Biological Physics, Rice University, Houston, TX, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Richard S Mann
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Louis Lambrechts
- Insect-Virus Interactions Group, Department of Genomes and Genetics, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique, Unité Mixte de Recherche 2000, Paris, France
| | - Jeffrey R Powell
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
| | - Maria V Sharakhova
- Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, USA.,Department of Entomology, Virginia Tech, Blacksburg, VA, USA.,Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, Tomsk, Russia
| | - Zhijian Tu
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, USA
| | - Hugh M Robertson
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Carolyn S McBride
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.,Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | | | | | - Daniel E Neafsey
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.,Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Adam M Phillippy
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Leslie B Vosshall
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY, USA.,Howard Hughes Medical Institute, New York, NY, USA.,Kavli Neural Systems Institute, New York, NY, USA
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11
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Dong D, Zhang Y, Smykal V, Ling L, Raikhel AS. HR38, an ortholog of NR4A family nuclear receptors, mediates 20-hydroxyecdysone regulation of carbohydrate metabolism during mosquito reproduction. Insect Biochem Mol Biol 2018; 96. [PMID: 29526770 PMCID: PMC5959765 DOI: 10.1016/j.ibmb.2018.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The Aedes aegypti mosquito is the principal vector for many dangerous human viral diseases. Carbohydrate metabolism (CM) is essential for supplying the energy necessary for host seeking, blood digestion and rapid egg development of this vector insect. The steroid hormone 20-hydroxyecdysone (20E) and the ecdysone receptor (EcR) are important regulators of CM, coordinating it with female reproductive events. We report here that the NR4A nuclear receptor AHR38 plays a critical role in mediating these actions of 20E and EcR. AHR38 RNA interference (RNAi) depletion in female mosquitoes blocked the transcriptional activation of CM genes encoding phosphoglucomutase (PGM) and trehalose-6-phophate synthase (TPS); it caused an increase of glycogen accumulation and a decrease of the circulating sugar trehalose. This treatment also resulted in a dramatic reduction in fecundity. Considering that these phenotypes resulting from AHR38 RNAi depletion are similar to those of EcR RNAi, we investigated a possible connection between these transcription factors in CM regulation. EcR RNAi inhibits the AHR38 gene expression. Moreover, the 20E-induced EcR complex directly activates AHR38 by binding to the ecdysone response element (EcRE) in the upstream regulatory region of this gene. The present work has implicated AHR38 in the 20E-mediated control of CM and provided new insight into mechanisms of 20E regulation of metabolism during female mosquito reproduction.
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Affiliation(s)
- Dujuan Dong
- Department of Entomology, University of California, Riverside, CA 92521, USA; Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan 250100, China
| | - Yang Zhang
- Department of Entomology, University of California, Riverside, CA 92521, USA; Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Vlastimil Smykal
- Department of Entomology, University of California, Riverside, CA 92521, USA
| | - Lin Ling
- Department of Entomology, University of California, Riverside, CA 92521, USA
| | - Alexander S Raikhel
- Department of Entomology, University of California, Riverside, CA 92521, USA; Institute for Integrative Genomic Biology, University of California, Riverside, CA 92521, USA.
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12
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Abstract
The synthesis of vitellogenin and its uptake by maturing oocytes during egg maturation are essential for successful female reproduction. These events are regulated by the juvenile hormones and ecdysteroids and by the nutritional signaling pathway regulated by neuropeptides. Juvenile hormones act as gonadotropins, regulating vitellogenesis in most insects, but ecdysteroids control this process in Diptera and some Hymenoptera and Lepidoptera. The complex crosstalk between the juvenile hormones, ecdysteroids, and nutritional signaling pathways differs distinctly depending on the reproductive strategies adopted by various insects. Molecular studies within the past decade have revealed much about the relationships among, and the role of, these pathways with respect to regulation of insect reproduction. Here, we review the role of juvenile hormones, ecdysteroids, and nutritional signaling, along with that of microRNAs, in regulating female insect reproduction at the molecular level.
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Affiliation(s)
- Sourav Roy
- Department of Entomology, Institute for Integrative Genome Biology, and Center for Disease Vector Research, University of California, Riverside, California 92521, USA; , ,
| | - Tusar T Saha
- Department of Entomology, Institute for Integrative Genome Biology, and Center for Disease Vector Research, University of California, Riverside, California 92521, USA; , ,
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China;
| | - Alexander S Raikhel
- Department of Entomology, Institute for Integrative Genome Biology, and Center for Disease Vector Research, University of California, Riverside, California 92521, USA; , ,
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13
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Pan X, Pike A, Joshi D, Bian G, McFadden MJ, Lu P, Liang X, Zhang F, Raikhel AS, Xi Z. The bacterium Wolbachia exploits host innate immunity to establish a symbiotic relationship with the dengue vector mosquito Aedes aegypti. ISME J 2017; 12:277-288. [PMID: 29099491 PMCID: PMC5739022 DOI: 10.1038/ismej.2017.174] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 08/30/2017] [Accepted: 09/06/2017] [Indexed: 01/15/2023]
Abstract
A host's immune system plays a central role in shaping the composition of the microbiota and, in return, resident microbes influence immune responses. Symbiotic associations of the maternally transmitted bacterium Wolbachia occur with a wide range of arthropods. It is, however, absent from the dengue and Zika vector mosquito Aedes aegypti in nature. When Wolbachia is artificially forced to form symbiosis with this new mosquito host, it boosts the basal immune response and enhances the mosquito's resistance to pathogens, including dengue, Zika virus and malaria parasites. The mechanisms involved in establishing a symbiotic relationship between Wolbachia and A. aegypti, and the long-term outcomes of this interaction, are not well understood. Here, we have demonstrated that both the immune deficiency (IMD) and Toll pathways are activated by the Wolbachia strain wAlbB upon its introduction into A. aegypti. Silencing the Toll and IMD pathways via RNA interference reduces the wAlbB load. Notably, wAlbB induces peptidoglycan recognition protein (PGRP)-LE expression in the carcass of A. aegypti, and its silencing results in a reduction of symbiont load. Using transgenic mosquitoes with stage-specific induction of the IMD and Toll pathways, we have shown that elevated wAlbB infection in these mosquitoes is maintained via maternal transmission. These results indicate that host innate immunity is utilized to establish and promote host-microbial symbiosis. Our results will facilitate a long-term projection of the stability of the Wolbachia-A. aegypti mosquito system that is being developed to control dengue and Zika virus transmission to humans.
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Affiliation(s)
- Xiaoling Pan
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.,School of Medicine, Hunan Normal University, Changsha, Hunan 410013, China
| | - Andrew Pike
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Deepak Joshi
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Guowu Bian
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Michael J McFadden
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Peng Lu
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Xiao Liang
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Fengrui Zhang
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Alexander S Raikhel
- Department of Entomology and Institute for Integrative Molecular Biology, University of California, Riverside, CA 92521, USA
| | - Zhiyong Xi
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.,Sun Yat-sen University-Michigan State University Joint Center of Vector Control for Tropical Diseases, Guangzhou, Guangdong 510080, China
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14
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Ling L, Kokoza VA, Zhang C, Aksoy E, Raikhel AS. MicroRNA-277 targets insulin-like peptides 7 and 8 to control lipid metabolism and reproduction in Aedes aegypti mosquitoes. Proc Natl Acad Sci U S A 2017; 114:E8017-E8024. [PMID: 28874536 PMCID: PMC5617303 DOI: 10.1073/pnas.1710970114] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Hematophagous female mosquitoes transmit numerous devastating human diseases, including malaria, dengue fever, Zika virus, and others. Because of their obligatory requirement of a vertebrate blood meal for reproduction, these mosquitoes need a lot of energy; therefore, understanding the molecular mechanisms linking metabolism and reproduction is of particular importance. Lipids are the major energy store providing the fuel required for host seeking and reproduction. They are essential components of the fat body, a metabolic tissue that is the insect analog of vertebrate liver and adipose tissue. In this study, we found that microRNA-277 (miR-277) plays an important role in regulating mosquito lipid metabolism. The genetic disruption of miR-277 using the CRISPR-Cas9 system led to failures in both lipid storage and ovary development. miR-277 mimic injection partially rescued these phenotypic manifestations. Examination of subcellular localization of FOXO protein via CRISPR-assisted, single-stranded oligodeoxynucleotide-mediated homology-directed repair revealed that insulin signaling is up-regulated in response to miR-277 depletion. In silico target prediction identified that insulin-like peptides 7 and 8 (ilp7 and ilp8) are putative targets of miR-277; RNA immunoprecipitation and a luciferase reporter assay confirmed that ilp7 and ilp8 are direct targets of this miRNA. CRISPR-Cas9 depletion of ilp7 and ilp8 led to metabolic and reproductive defects. These depletions identified differential actions of ILP7 and ILP8 in lipid homeostasis and ovarian development. Thus, miR-277 plays a critical role in mosquito lipid metabolism and reproduction by targeting ilp7 and ilp8, and serves as a monitor to control ILP7 and ILP8 mRNA levels.
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Affiliation(s)
- Lin Ling
- Department of Entomology, University of California, Riverside, CA 92521
- Institute of Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Vladimir A Kokoza
- Department of Entomology, University of California, Riverside, CA 92521
| | - Changyu Zhang
- Department of Entomology, University of California, Riverside, CA 92521
| | - Emre Aksoy
- Department of Entomology, University of California, Riverside, CA 92521
- Graduate Program in Genetics, Genomics, and Bioinformatics, University of California, Riverside, CA 92521
| | - Alexander S Raikhel
- Department of Entomology, University of California, Riverside, CA 92521;
- Institute of Integrative Genome Biology, University of California, Riverside, CA 92521
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15
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Zhao B, Lucas KJ, Saha TT, Ha J, Ling L, Kokoza VA, Roy S, Raikhel AS. MicroRNA-275 targets sarco/endoplasmic reticulum Ca2+ adenosine triphosphatase (SERCA) to control key functions in the mosquito gut. PLoS Genet 2017; 13:e1006943. [PMID: 28787446 PMCID: PMC5560755 DOI: 10.1371/journal.pgen.1006943] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 08/17/2017] [Accepted: 07/26/2017] [Indexed: 12/17/2022] Open
Abstract
The yellow fever mosquito Aedes aegypti is the major vector of arboviruses, causing numerous devastating human diseases, such as dengue and yellow fevers, Chikungunya and Zika. Female mosquitoes need vertebrate blood for egg development, and repeated cycles of blood feeding are tightly linked to pathogen transmission. The mosquito’s posterior midgut (gut) is involved in blood digestion and also serves as an entry point for pathogens. Thus, the mosquito gut is an important tissue to investigate. The miRNA aae-miR-275 (miR-275) has been shown to be required for normal blood digestion in the female mosquito; however, the mechanism of its action has remained unknown. Here, we demonstrate that miR-275 directly targets and positively regulates sarco/endoplasmic reticulum Ca2+adenosine triphosphatase, which is implicated in active transport of Ca2+ from the cytosol to the sarco/endoplasmic reticulum. We utilized a combination of the gut-specific yeast transcription activator protein Gal4/upstream activating sequence (Gal4/UAS) system and miRNA Tough Decoy technology to deplete the endogenous level of miR-275 in guts of transgenic mosquitoes. This gut-specific reduction of miR-275 post blood meal decreased SERCA mRNA and protein levels of the digestive enzyme late trypsin. It also resulted in a significant reduction of gut microbiota. Moreover, the decrease of miR-275 and SERCA correlated with defects in the Notch signaling pathway and assembly of the gut actin cytoskeleton. The adverse phenotypes caused by miR-275 silencing were rescued by injections of miR-275 mimic. Thus, we have discovered that miR-275 directly targets SERCA, and the maintenance of its level is critical for multiple gut functions in mosquitoes. Female mosquitoes transmit numerous devastating human diseases. The mosquito gut, in addition to its primary function as a site of blood digestion, represents the entry point for pathogen colonization in mosquito vectors. The conserved microRNA, miR-275, was shown to be required for blood digestion and egg development. In this study, we investigated the target of miR-275 contributing to the regulation of mosquito gut functions. We achieved spatiotemporal suppression of miR-275 using a transgenic Tough Decoy RNA approach in the A. aegypti female mosquito gut. Furthermore, we have uncovered that miR-275 targets sarco/endoplasmic reticulum Ca2+- adenosine triphosphatase (SERCA), affecting numerous gut functions including blood digestion, production of digestive proteases, and assembly of the gut actin cytoskeleton. SERCA is essential for maintenance of Ca2+ homeostasis, and its disturbance, in humans, leads to cardiac hypertrophy, heart failure and cancers. Therefore, the finding that the miRNA miR-275 targets SERCA not only contributes to the knowledge of mosquito gut regulation but also significantly adds to the general understanding of mechanisms governing this critical molecule.
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Affiliation(s)
- Bo Zhao
- Department of Entomology and Institute for Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
| | - Keira J Lucas
- Department of Entomology and Institute for Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
| | - Tusar T Saha
- Department of Entomology and Institute for Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
| | - Jisu Ha
- Department of Entomology and Institute for Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
- Graduate Program in Genetics, Genomics and Bioinformatics, University of California Riverside, Riverside, California, United States of America
| | - Lin Ling
- Department of Entomology and Institute for Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
| | - Vladimir A Kokoza
- Department of Entomology and Institute for Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
| | - Sourav Roy
- Department of Entomology and Institute for Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
| | - Alexander S Raikhel
- Department of Entomology and Institute for Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
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16
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Wang JL, Saha TT, Zhang Y, Zhang C, Raikhel AS. Juvenile hormone and its receptor methoprene-tolerant promote ribosomal biogenesis and vitellogenesis in the Aedes aegypti mosquito. J Biol Chem 2017; 292:10306-10315. [PMID: 28446607 DOI: 10.1074/jbc.m116.761387] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 04/24/2017] [Indexed: 12/24/2022] Open
Abstract
Juvenile hormone (JH) controls many biological activities in insects, including development, metamorphosis, and reproduction. In the Aedes aegypti mosquito, a vector of dengue, yellow fever, chikungunya, and zika viruses, the metabolic tissue (the fat body, which is an analogue of the vertebrate liver) produces yolk proteins for developing oocytes. JH is important for the fat body to acquire competence for yolk protein production. However, the molecular mechanisms of how JH promotes mosquito reproduction are not completely understood. In this study we show that stimulation of the JH receptor methoprene-tolerant (Met) activates expression of genes encoding the regulator of ribosome synthesis 1 (RRS1) and six ribosomal proteins (two ribosomal large subunit proteins, two ribosomal small subunit proteins, and two mitochondrial ribosomal proteins). Moreover, RNAi-mediated depletion of RRS1 decreased biosynthesis of the ribosomal protein L32 (RpL32). Depletion of Met, RRS1, or RpL32 led to retardation of ovarian growth and reduced mosquito fecundity, which may at least in part have resulted from decreased vitellogenin protein production in the fat body. In summary, our results indicate that JH is critical for inducing the expression of ribosomal protein genes and demonstrate that RRS1 mediates the JH signal to enhance both ribosomal biogenesis and vitellogenesis.
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Affiliation(s)
- Jia-Lin Wang
- From the Department of Entomology, University of California, Riverside, California 92521.,Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
| | - Tusar T Saha
- From the Department of Entomology, University of California, Riverside, California 92521.,Institute for Integrative Genomic Biology, University of California, Riverside, California 92521
| | - Yang Zhang
- From the Department of Entomology, University of California, Riverside, California 92521.,Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China, and
| | - Changyu Zhang
- From the Department of Entomology, University of California, Riverside, California 92521.,Guizhou Key Laboratory for Plant Pest Management of Mountain Region, College of Agriculture, Guizhou University, Guiyang 550025, China
| | - Alexander S Raikhel
- From the Department of Entomology, University of California, Riverside, California 92521, .,Institute for Integrative Genomic Biology, University of California, Riverside, California 92521
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Lucas KJ, Zhao B, Roy S, Gervaise AL, Raikhel AS. Mosquito-specific microRNA-1890 targets the juvenile hormone-regulated serine protease JHA15 in the female mosquito gut. RNA Biol 2016; 12:1383-90. [PMID: 26488481 DOI: 10.1080/15476286.2015.1101525] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Females of the hematophagous mosquito species require a vertebrate blood meal to supply amino acids and other nutrients necessary for egg development, serving as the driving force for the spread of many vector-borne diseases in humans. Blood digestion utilizes both early and late phase serine proteases (SPs) that are differentially regulated at the transcriptional and post-transcriptional level. To uncover the regulatory complexity of SPs in the female mosquito midgut, we investigated involvement of miRNAs in regulating the juvenile hormone (JH)-controlled chymotrypsin-like SP, JHA15. We identified regulatory regions complementary to the mosquito-specific miRNA, miR-1890, within the 3' UTR of JHA15 mRNA. The level of the JHA15 transcript is highest post eclosion and drastically declines post blood meal (PBM), exhibiting an opposite trend to miR-1890 that peaks at 24 h PBM. Depletion of miR-1890 results in defects in blood digestion, ovary development and egg deposition. JHA15 mRNA and protein levels are elevated in female mosquitoes with miR-1890 inhibition. JHA15 RNA interference in the miR-1890 depletion background alleviates miR-1890 depletion phenotypes. The miR-1890 gene is activated by the 20-hydroxyecdysone pathway that involves the ecdysone receptor and the early genes, E74B and Broad Z2. Our study suggests that miR-1890 controls JHA15 mRNA stability in a stage- and tissue- specific manner.
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Affiliation(s)
- Keira J Lucas
- a Department of Entomology ; University of California, Riverside ; Riverside , CA USA.,b Graduate Program in Genetics; Genomics and Bioinformatics; University of California Riverside , Riverside , CA USA
| | - Bo Zhao
- a Department of Entomology ; University of California, Riverside ; Riverside , CA USA.,c Institute for Integrative Genome Biology; University of California Riverside , Riverside , CA USA
| | - Sourav Roy
- a Department of Entomology ; University of California, Riverside ; Riverside , CA USA.,c Institute for Integrative Genome Biology; University of California Riverside , Riverside , CA USA
| | - Amanda L Gervaise
- a Department of Entomology ; University of California, Riverside ; Riverside , CA USA
| | - Alexander S Raikhel
- a Department of Entomology ; University of California, Riverside ; Riverside , CA USA.,c Institute for Integrative Genome Biology; University of California Riverside , Riverside , CA USA
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Zhao B, Hou Y, Wang J, Kokoza VA, Saha TT, Wang XL, Lin L, Zou Z, Raikhel AS. Determination of juvenile hormone titers by means of LC-MS/MS/MS and a juvenile hormone-responsive Gal4/UAS system in Aedes aegypti mosquitoes. Insect Biochem Mol Biol 2016; 77:69-77. [PMID: 27530057 PMCID: PMC5028310 DOI: 10.1016/j.ibmb.2016.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 08/09/2016] [Accepted: 08/10/2016] [Indexed: 05/16/2023]
Abstract
In anautogenous mosquitoes, juvenile hormone III (JH) plays an essential role in female post-eclosion (PE) development, preparing them for subsequent blood feeding and egg growth. We re-examined the JH titer during the reproductive cycle of female Aedes aegypti mosquitoes. Using liquid chromatography coupled with triple tandem mass spectrometry (LC-MS/MS/MS), we have shown that it reaches its peak at 48-54 h PE in the female hemolymph and at 72 h PE in whole body extracts. This method represents an effective assay for determination of JH titers. The 2.1-kb 5' promoter region of the Early Trypsin (ET) gene, which is specifically expressed in the female midgut under the control of JH during the PE phase, was utilized to genetically engineer the Ae. aegypti mosquito line with the ET-Gal4 activator. We then established the ET-GAL4>UAS-enhanced green fluorescent protein (EGFP) system in Ae. aegypti. In ET-Gal4>UAS-EGFP female mosquitoes, the intensity of the midgut-specific EGFP signal was observed to correspond to the ET gene transcript level and follow the JH titer during the PE phase. The EGFP signal and the EGFP transcript level were significantly diminished in midguts of transgenic female mosquitoes after RNA interference depletion of the JH receptor Methoprene-tolerant (Met), providing evidence of the control of ET gene expression by Met. Topical JH application caused premature enhancement of the EGFP signal and the EGFP transcript level in midguts of newly eclosed ET-Gal4>UAS-EGFP female mosquitoes, in which endogenous JH titer is still low. Hence, this novel ET-Gal4>UAS system permits JH-dependent gene overexpression in the midgut of Ae. aegypti female mosquitoes prior to a blood meal.
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Affiliation(s)
- Bo Zhao
- Department of Entomology, University of California, Riverside, CA, 92521, USA
| | - Yuan Hou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jianjun Wang
- Department of Entomology, University of California, Riverside, CA, 92521, USA; College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, 225009, China
| | - Vladimir A Kokoza
- Department of Entomology, University of California, Riverside, CA, 92521, USA
| | - Tusar T Saha
- Department of Entomology, University of California, Riverside, CA, 92521, USA
| | - Xue-Li Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ling Lin
- Department of Entomology, University of California, Riverside, CA, 92521, USA
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Alexander S Raikhel
- Department of Entomology, University of California, Riverside, CA, 92521, USA; The Institute for Integrative Genome Biology, University of California, Riverside, CA, 92521, USA.
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Abstract
The amino acid-Target of Rapamycin (AA/TOR) and insulin pathways play a pivotal role in reproduction of female insects, serving as regulatory checkpoints that guarantee the sufficiency of nutrients for developing eggs. Being evolutionary older, the AA/TOR pathway functions as an initial nutritional sensor that not only activates nutritional responses in a tissue-specific manner, but is also involved in the control of insect insulin-like peptides (ILPs) secretion. Insulin and AA/TOR pathways also assert their nutritionally linked influence on reproductive events by contributing to the control of biosynthesis and secretion of juvenile hormone and ecdysone. This review covers the present status of our understanding of the contributions of AA/TOR and insulin pathways in insect reproduction.
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Affiliation(s)
| | - Alexander S. Raikhel
- Corresponding author. Department of Entomology, University of California Riverside, Riverside, CA 92521, USA. Tel.: 951 827 2129
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20
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Abstract
MicroRNAs (miRNAs) are small non-coding RNAs that function in gene regulatory processes in plants and animals by targeting sites within messenger RNA. In insects, miRNAs have been shown to regulate a variety of physiological processes throughout insect development, including molting, metamorphosis, oogenesis, embryogenesis, behavior and host-pathogen interactions. The roles of miRNAs in the model organism, Drosophila melanogaster, have been studied extensively due to the conserved nature of miRNA function among highly divergent species. However, seeking to understand miRNA function in non-drosophilid insect species has become a growing trend in insect science. Here, we highlight the recent discoveries regarding miRNA function in insect physiology and development.
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Affiliation(s)
- Keira J. Lucas
- Department of Entomology, University of California Riverside CA 92521, USA
- Graduate Program in Genetics, Genomics and Bioinformatics, University of California Riverside CA 92521, USA
| | - Bo Zhao
- Department of Entomology, University of California Riverside CA 92521, USA
- Institute for Integrative Genome Biology, University of California Riverside CA 92521, USA
| | - Shiping Liu
- The State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Alexander S. Raikhel
- Department of Entomology, University of California Riverside CA 92521, USA
- Institute for Integrative Genome Biology, University of California Riverside CA 92521, USA
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21
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Yamanaka N, Raikhel AS. Editorial overview: Molecular physiology: Toward unified comprehension of insect physiological systems. Curr Opin Insect Sci 2015; 11:vii-viii. [PMID: 28285766 DOI: 10.1016/j.cois.2015.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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Roy S, Saha TT, Johnson L, Zhao B, Ha J, White KP, Girke T, Zou Z, Raikhel AS. Regulation of Gene Expression Patterns in Mosquito Reproduction. PLoS Genet 2015; 11:e1005450. [PMID: 26274815 PMCID: PMC4537244 DOI: 10.1371/journal.pgen.1005450] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/17/2015] [Indexed: 12/14/2022] Open
Abstract
In multicellular organisms, development, growth and reproduction require coordinated expression of numerous functional and regulatory genes. Insects, in addition to being the most speciose animal group with enormous biological and economical significance, represent outstanding model organisms for studying regulation of synchronized gene expression due to their rapid development and reproduction. Disease-transmitting female mosquitoes have adapted uniquely for ingestion and utilization of the huge blood meal required for swift reproductive events to complete egg development within a 72-h period. We investigated the network of regulatory factors mediating sequential gene expression in the fat body, a multifunctional organ analogous to the vertebrate liver and adipose tissue, of the female Aedes aegypti mosquito. Transcriptomic and bioinformatics analyses revealed that ~7500 transcripts are differentially expressed in four sequential waves during the 72-h reproductive period. A combination of RNA-interference gene-silencing and in-vitro organ culture identified the major regulators for each of these waves. Amino acids (AAs) regulate the first wave of gene activation between 3 h and 12 h post-blood meal (PBM). During the second wave, between 12 h and 36 h, most genes are highly upregulated by a synergistic action of AAs, 20-hydroxyecdysone (20E) and the Ecdysone-Receptor (EcR). Between 36 h and 48 h, the third wave of gene activation—regulated mainly by HR3—occurs. Juvenile Hormone (JH) and its receptor Methoprene-Tolerant (Met) are major regulators for the final wave between 48 h and 72 h. Each of these key regulators also has repressive effects on one or more gene sets. Our study provides a better understanding of the complexity of the regulatory mechanisms related to temporal coordination of gene expression during reproduction. We have detected the novel function of 20E/EcR responsible for transcriptional repression. This study also reveals the previously unidentified large-scale effects of HR3 and JH/Met on transcriptional regulation during the termination of vitellogenesis and remodeling of the fat body. In addition to being vectors of devastating human diseases, mosquitoes represent outstanding model organisms for studying regulatory mechanisms of differential gene expression due to their rapid reproductive cycles. About 7500 transcripts are differentially expressed in four sequential waves during the 72-h reproductive period in the fat body, a critical reproductive organ. The major regulators for these waves of gene expression are the two very important insect hormones, 20-hydroxyecdysone (20E) and Juvenile hormone (JH), their respective receptors Ecdysone Receptor (EcR) and Methoprene-Tolerant (Met), amino acids and the orphan nuclear receptor HR3. These key regulators are responsible for activation and repression of co-regulated gene sets, at different time points, within the 72-h reproductive period. Importantly, this study, apart from providing an insight into the regulatory complexity involved in the temporal coordination of gene expression, also reveals the previously unidentified roles of 20E/EcR, JH/Met and HR3 during the 72-h period post blood meal.
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Affiliation(s)
- Sourav Roy
- Department of Entomology, University of California, Riverside, Riverside, California, United States of America
- Institute of Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
| | - Tusar T. Saha
- Department of Entomology, University of California, Riverside, Riverside, California, United States of America
- Institute of Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
| | - Lisa Johnson
- Department of Entomology, University of California, Riverside, Riverside, California, United States of America
- Institute of Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
- Graduate Program in Cell, Molecular and Developmental Biology, University of California, Riverside, Riverside, California, United States of America
| | - Bo Zhao
- Department of Entomology, University of California, Riverside, Riverside, California, United States of America
- Institute of Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
| | - Jisu Ha
- Department of Entomology, University of California, Riverside, Riverside, California, United States of America
- Institute of Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
- Graduate Program in Genetics, Genomics and Bioinformatics, University of California, Riverside, Riverside, California, United States of America
| | - Kevin P. White
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, Illinois, United States of America
| | - Thomas Girke
- Institute of Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, California, United States of America
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- * E-mail: (ZZ); (ASR)
| | - Alexander S. Raikhel
- Department of Entomology, University of California, Riverside, Riverside, California, United States of America
- Institute of Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
- * E-mail: (ZZ); (ASR)
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Hou Y, Wang XL, Saha TT, Roy S, Zhao B, Raikhel AS, Zou Z. Temporal Coordination of Carbohydrate Metabolism during Mosquito Reproduction. PLoS Genet 2015; 11:e1005309. [PMID: 26158648 PMCID: PMC4497655 DOI: 10.1371/journal.pgen.1005309] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 05/28/2015] [Indexed: 11/18/2022] Open
Abstract
Hematophagous mosquitoes serve as vectors of multiple devastating human diseases, and many unique physiological features contribute to the incredible evolutionary success of these insects. These functions place high-energy demands on a reproducing female mosquito, and carbohydrate metabolism (CM) must be synchronized with these needs. Functional analysis of metabolic gene profiling showed that major CM pathways, including glycolysis, glycogen and sugar metabolism, and citrate cycle, are dramatically repressed at post eclosion (PE) stage in mosquito fat body followed by a sharply increase at post-blood meal (PBM) stage, which were also verified by Real-time RT-PCR. Consistent to the change of transcript and protein level of CM genes, the level of glycogen, glucose and trehalose and other secondary metabolites are also periodically accumulated and degraded during the reproductive cycle respectively. Levels of triacylglycerols (TAG), which represent another important energy storage form in the mosquito fat body, followed a similar tendency. On the other hand, ATP, which is generated by catabolism of these secondary metabolites, showed an opposite trend. Additionally, we used RNA interference studies for the juvenile hormone and ecdysone receptors, Met and EcR, coupled with transcriptomics and metabolomics analyses to show that these hormone receptors function as major regulatory switches coordinating CM with the differing energy requirements of the female mosquito throughout its reproductive cycle. Our study demonstrates how, by metabolic reprogramming, a multicellular organism adapts to drastic and rapid functional changes. Mosquitoes transmit numerous devastating human diseases due to their obligatory hematophagy that is required for the efficient reproduction. Metabolism must be synchronized with high energetic needs of a female mosquito for host seeking, blood feeding and rapid egg development. Each reproductive cycle is divided into two phases that are sequentially governed by juvenile hormone (JH) and 20-hydroxyecdysone. During the pre-blood meal phase, the JH receptor Methoprene-tolerant (Met) controls carbohydrate metabolism (CM) pathways and its RNA interference (RNAi) silencing caused up-regulation of CM enzymes at the transcript and protein levels activating glycolytic flux and depletion of storage and circulating sugars. During the second, post blood meal phase, CM was regulated by the ecdysone receptor EcR and its RNAi silencing had a dramatic effect opposite to that of Met RNAi. Thus, we show that Met and EcR function as regulatory switches coordinating carbohydrate metabolism with energetic requirements of the female mosquito reproductive cycle.
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Affiliation(s)
- Yuan Hou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xue-Li Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Tusar T. Saha
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
| | - Sourav Roy
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
| | - Bo Zhao
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
| | - Alexander S. Raikhel
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
- * E-mail: (ASR); (ZZ)
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- * E-mail: (ASR); (ZZ)
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Wang YH, Hu Y, Xing LS, Jiang H, Hu SN, Raikhel AS, Zou Z. A Critical Role for CLSP2 in the Modulation of Antifungal Immune Response in Mosquitoes. PLoS Pathog 2015; 11:e1004931. [PMID: 26057557 PMCID: PMC4461313 DOI: 10.1371/journal.ppat.1004931] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 05/04/2015] [Indexed: 11/18/2022] Open
Abstract
Entomopathogenic fungi represent a promising class of bio-insecticides for mosquito control. Thus, detailed knowledge of the molecular mechanisms governing anti-fungal immune response in mosquitoes is essential. In this study, we show that CLSP2 is a modulator of immune responses during anti-fungal infection in the mosquito Aedes aegypti. With a fungal infection, the expression of the CLSP2 gene is elevated. CLSP2 is cleaved upon challenge with Beauveria bassiana conidia, and the liberated CLSP2 CTL-type domain binds to fungal cell components and B. bassiana conidia. Furthermore, CLPS2 RNA interference silencing significantly increases the resistance to the fungal challenge. RNA-sequencing transcriptome analysis showed that the majority of immune genes were highly upregulated in the CLSP2-depleted mosquitoes infected with the fungus. The up-regulated immune gene cohorts belong to melanization and Toll pathways, but not to the IMD or JAK-STAT. A thioester-containing protein (TEP22), a member of α2-macroglobulin family, has been implicated in the CLSP2-modulated mosquito antifungal defense. Our study has contributed to a greater understanding of immune-modulating mechanisms in mosquitoes.
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Affiliation(s)
- Yan-Hong Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Yang Hu
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Long-Sheng Xing
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hong Jiang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Song-Nian Hu
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Alexander S. Raikhel
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
- * E-mail: (ASR); (ZZ)
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- * E-mail: (ASR); (ZZ)
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Zhao B, Kokoza VA, Saha TT, Wang S, Roy S, Raikhel AS. Regulation of the gut-specific carboxypeptidase: a study using the binary Gal4/UAS system in the mosquito Aedes aegypti. Insect Biochem Mol Biol 2014; 54:1-10. [PMID: 25152428 PMCID: PMC4426967 DOI: 10.1016/j.ibmb.2014.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/31/2014] [Accepted: 08/03/2014] [Indexed: 05/26/2023]
Abstract
Pathogen transmission by mosquitoes is tightly linked to blood feeding which, in turn, is required for egg development. Studies of these processes would greatly benefit from genetic methods, such as the binary Gal4/UAS system. The latter has been well established for model organisms, but its availability is limited for mosquitoes. The objective of this study was to develop the blood-meal-activated, gut-specific Gal4/UAS system for the yellow-fever mosquito Aedes aegypti and utilize it to investigate the regulation of gut-specific gene expression. A 1.1-kb, 5(') upstream region of the carboxypeptidase A (CP) gene was used to genetically engineer the CP-Gal4 driver mosquito line. The CP-Gal4 specifically activated the Enhanced Green Fluorescent Protein (EGFP) reporter only after blood feeding in the gut of the CP-Gal4 > UAS-EGFP female Ae. aegypti. We used this system to study the regulation of CP gene expression. In vitro treatments with either amino acids (AAs) or insulin stimulated expression of the CP-Gal4 > UAS-EGFP transgene; no effect was observed with 20-hydroxyecdysone (20E) treatments. The transgene activation by AAs and insulin was blocked by rapamycin, the inhibitor of the Target-of-Rapamycin (TOR) kinase. RNA interference (RNAi) silence of the insulin receptor (IR) reduced the expression of the CP-Gal4 > UAS-EGFP transgene. Thus, in vitro and in vivo experiments have revealed that insulin and TOR pathways control expression of the digestive enzyme CP. In contrast, 20E, the major regulator of post-blood-meal vitellogenic events in female mosquitoes, has no role in regulating the expression of this gene. This novel CP-Gal4/UAS system permits functional testing of midgut-specific genes that are involved in blood digestion and interaction with pathogens in Ae. aegypti mosquitoes.
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Affiliation(s)
- Bo Zhao
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA; Graduate Program in Genetics, Genomics and Bioinformatics, University of California Riverside, Riverside, CA 92521, USA.
| | - Vladimir A Kokoza
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA; The Institute for Integrative Genome Biology, University of California Riverside, Riverside, CA 92521, USA.
| | - Tusar T Saha
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA; The Institute for Integrative Genome Biology, University of California Riverside, Riverside, CA 92521, USA.
| | - Stephanie Wang
- Honors Undergraduate Program, University of California Riverside, Riverside, CA 92521, USA.
| | - Sourav Roy
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA; The Institute for Integrative Genome Biology, University of California Riverside, Riverside, CA 92521, USA.
| | - Alexander S Raikhel
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA; The Institute for Integrative Genome Biology, University of California Riverside, Riverside, CA 92521, USA.
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26
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Lucas KJ, Myles KM, Raikhel AS. Small RNAs: a new frontier in mosquito biology. Trends Parasitol 2013; 29:295-303. [PMID: 23680188 DOI: 10.1016/j.pt.2013.04.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 04/06/2013] [Accepted: 04/08/2013] [Indexed: 12/23/2022]
Abstract
The discovery of small non-coding RNAs has revolutionized our understanding of regulatory networks governing multiple functions in animals and plants. However, our knowledge of mosquito small RNAs is limited. We discuss here the state of current knowledge regarding the roles of small RNAs and their targets in mosquitoes, and describe the ongoing efforts to understand the role of the RNA interference (RNAi) pathway in mosquito antiviral immunity and transposon silencing. Providing a clear picture into the role of small RNAs in mosquito vectors will pave the way to the utilization of these small molecules in developing novel control approaches that target mosquito immunity and/or reproductive events. Elucidation of the functions of small RNAs represents a new frontier in mosquito biology.
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Affiliation(s)
- Keira J Lucas
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA
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27
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Lucas K, Raikhel AS. Insect microRNAs: biogenesis, expression profiling and biological functions. Insect Biochem Mol Biol 2013; 43:24-38. [PMID: 23165178 PMCID: PMC3534889 DOI: 10.1016/j.ibmb.2012.10.009] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 10/24/2012] [Accepted: 10/28/2012] [Indexed: 05/09/2023]
Abstract
MicroRNAs (miRNA) are a class of endogenous regulatory RNA molecules 21-24 nucleotides in length that modulate gene expression at the post-transcriptional level via base pairing to target sites within messenger RNAs (mRNA). Typically, the miRNA "seed sequence" (nucleotides 2-8 at the 5' end) binds complementary seed match sites within the 3' untranslated region of mRNAs, resulting in either translational inhibition or mRNA degradation. MicroRNAs were first discovered in Caenorhabditis elegans and were shown to be involved in the timed regulation of developmental events. Since their discovery in the 1990s, thousands of potential miRNAs have since been identified in various organisms through small RNA cloning methods and/or computational prediction, and have been shown to play functionally important roles of gene regulation in invertebrates, vertebrates, plants, fungi and viruses. Numerous functions of miRNAs identified in Drosophila melanogaster have demonstrated a great significance of these regulatory molecules. However, elucidation of miRNA roles in non-drosophilid insects presents a challenging and important task.
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Affiliation(s)
- Keira Lucas
- Department of Entomology, University of California Riverside, Riverside, CA 92521, U.S.A
- Institute for Integrative Genome Biology, University of California Riverside, Riverside, CA 92521, U.S.A
- Graduate Program in Genetics, Genomics and Bioinformatics, University of California Riverside, Riverside, CA 92521, U.S.A
| | - Alexander S. Raikhel
- Department of Entomology, University of California Riverside, Riverside, CA 92521, U.S.A
- Institute for Integrative Genome Biology, University of California Riverside, Riverside, CA 92521, U.S.A
- Corresponding author. Department of Entomology, University of California, Riverside, Riverside, CA 92521, U.S.A. Tel. +1 951 827 2129. (Keira Lucas); (Alexander S. Raikhel)
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Mane-Padros D, Cruz J, Cheng A, Raikhel AS. A critical role of the nuclear receptor HR3 in regulation of gonadotrophic cycles of the mosquito Aedes aegypti. PLoS One 2012; 7:e45019. [PMID: 23049766 PMCID: PMC3458863 DOI: 10.1371/journal.pone.0045019] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 08/14/2012] [Indexed: 11/25/2022] Open
Abstract
The orphan nuclear receptor HR3 is essential for developmental switches during insect development and metamorphosis regulated by 20-hydroxyecdysone (20E). Reproduction of female mosquitoes of the major vector of Dengue fever, Aedes aegypti, is cyclic because of its dependence on blood feeding. 20E is an important hormone regulating vitellogenic events in this mosquito; however, any role for HR3 in 20E-driven reproductive events has not been known. Using RNA interference (RNAi) approach, we demonstrated that Aedes HR3 plays a critical role in a timely termination of expression of the vitellogenin (Vg) gene encoding the major yolk protein precursor. It is also important for downregulation of the Target-of-Rapamycin pathway and activation of programmed autophagy in the Aedes fat body at the end of vitellogenesis. HR3 is critical in activating betaFTZ-F1, EcRB and USPA, the expressions of which are highly elevated at the end of vitellogenesis. RNAi depletion of HR3 (iHR3) prior to the first gonadotrophic cycle affects a normal progression of the second gonadotrophic cycle. Most of ovaries 24 h post second blood meal from iHR3 females in the second cycle were small with follicles that were only slightly different in length from of those of resting stage. In addition, these iHR3 females laid a significantly reduced number of eggs per mosquito as compared to those of iMal and the wild type. Our results indicate an important role of HR3 in regulation of 20E-regulated developmental switches during reproductive cycles of A. aegypti females.
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Affiliation(s)
- Daniel Mane-Padros
- Department of Entomology and Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
| | - Josefa Cruz
- Department of Entomology and Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
| | - Andrew Cheng
- Department of Entomology and Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
| | - Alexander S. Raikhel
- Department of Entomology and Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
- * E-mail:
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Cruz J, Mane-Padros D, Zou Z, Raikhel AS. Distinct roles of isoforms of the heme-liganded nuclear receptor E75, an insect ortholog of the vertebrate Rev-erb, in mosquito reproduction. Mol Cell Endocrinol 2012; 349:262-71. [PMID: 22115961 PMCID: PMC3306807 DOI: 10.1016/j.mce.2011.11.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 10/15/2011] [Accepted: 11/07/2011] [Indexed: 11/24/2022]
Abstract
Mosquitoes are adapted to using vertebrate blood as a nutrient source to promote egg development and as a consequence serve as disease vectors. Blood-meal activated reproductive events in female mosquitoes are hormonally and nutritionally controlled with an insect steroid hormone 20-hydroxyecdysone (20E) playing a central role. The nuclear receptor E75 is an essential factor in the 20E genetic hierarchy, however functions of its three isoforms - E75A, E75B, and E75C - in mosquito reproduction are unclear. By means of specific RNA interference depletion of E75 isoforms, we identified their distinct roles in regulating the level and timing of expression of key genes involved in vitellogenesis in the fat body (an insect analog of vertebrate liver and adipose tissue) of the mosquito Aedes aegypti. Heme is required in a high level of expression of 20E-controlled genes in the fat body, and this heme action depends on E75. Thus, in mosquitoes, heme is an important signaling molecule, serving as a sensor of the availability of a protein meal for egg development. Disruption of this signaling pathway could be explored in the design of mosquito control approaches.
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Affiliation(s)
| | | | | | - Alexander S. Raikhel
- Corresponding author: Department of Entomology and Institute of Integrative Genome Biology, 900 University Avenue, Riverside, CA 92521, USA. Tel: +1 951 827 2129;
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Abstract
Mosquitoes require blood for egg development, and, as a consequence, they transmit pathogens of devastating diseases. Target of rapamycin (TOR) signaling is a key pathway linking blood feeding and egg development in the mosquito Aedes aegypti. We show that the regulation of the TOR effector translational repressor 4E-BP is finely tuned to the nutritional requirements of the female mosquito, and it occurs at transcriptional and post-translational levels. Immediately after blood feeding, 4E-BP became hyperphosphorylated, suggesting rapid inhibition of its translational repression function. 4E-BP was highly phosphorylated after in vitro incubation of the fat body in the presence of amino acids; this phosphorylation was rapamycin insensitive, in contrast to another TOR target, S6K, phosphorylation of which was rapamycin sensitive. A high level of 4E-BP phosphorylation was also elicited by insulin. Rapamycin and the PI3K inhibitor LY294002 blocked insulin-mediated 4E-BP phosphorylation. RNA-interference depletion of the insulin receptor or Akt resulted in severe reduction of 4E-BP phosphorylation. Phosphorylation and stability of 4E-BP was dependent on its partner eIF4E translation initiation factor. Silencing of 4E-BP resulted in reduction of the life span of adult female mosquitoes. This study demonstrates a dual nutritional and hormonal control of 4E-BP and its role in mosquito egg development.
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Affiliation(s)
- Saurabh G Roy
- Department of Entomology, University of California Riverside, 900 University Ave., Riverside, CA 92521, USA
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Abstract
Autophagy plays a pivotal role by allowing cells to recycle cellular components under conditions of stress, starvation, development and cancer. In this work, we have demonstrated that programmed autophagy in the mosquito fat body plays a critical role in maintaining of developmental switches required for normal progression of gonadotrophic cycles. Mosquitoes must feed on vertebrate blood for their egg development, with each gonadotrophic cycle being tightly coupled to a separate blood meal. As a consequence, some mosquito species are vectors of pathogens that cause devastating diseases in humans and domestic animals, most importantly malaria and Dengue fever. Hence, deciphering mechanisms to control egg developmental cycles is of paramount importance for devising novel approaches for mosquito control. Central to egg development is vitellogenesis, the production of yolk protein precursors in the fat body, the tissue analogous to a vertebrate liver, and their subsequent specific accumulation in developing oocytes. During each egg developmental cycle, the fat body undergoes a developmental program that includes previtellogenic build-up of biosynthetic machinery, intense production of yolk protein precursors, and termination of vitellogenesis. The importance of autophagy for termination of vitellogenesis was confirmed by RNA interference (RNAi) depletions of several autophagic genes (ATGs), which inhibited autophagy and resulted in untimely hyper activation of TOR and prolonged production of the major yolk protein precursor, vitellogenin (Vg). RNAi depletion of the ecdysone receptor (EcR) demonstrated its activating role of autophagy. Depletion of the autophagic genes and of EcR led to inhibition of the competence factor, betaFTZ-F1, which is required for ecdysone-mediated developmental transitions. Moreover, autophagy-incompetent female mosquitoes were unable to complete the second reproductive cycle and exhibited retardation and abnormalities in egg maturation. Thus, our study has revealed a novel function of programmed autophagy in maintaining egg maturation cycles in mosquitoes.
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Affiliation(s)
- Bart Bryant
- Department of Entomology, Institute for Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
| | - Alexander S. Raikhel
- Department of Entomology, Institute for Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America
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Kokoza VA, Raikhel AS. Targeted gene expression in the transgenic Aedes aegypti using the binary Gal4-UAS system. Insect Biochem Mol Biol 2011; 41:637-44. [PMID: 21536128 PMCID: PMC3124619 DOI: 10.1016/j.ibmb.2011.04.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 04/11/2011] [Accepted: 04/13/2011] [Indexed: 05/04/2023]
Abstract
In this study, we report the establishment of the binary Gal4/UAS system for the yellow fever mosquito Aedes aegypti. We utilized the 1.8-kb 5' upstream region of the vitellogenin gene (Vg) to genetically engineer mosquito lines with the Vg-Gal4 activator and established UAS-EGFP responder transgenic mosquito lines to evaluate the binary Gal4/UAS system. The results show that the Vg-Gal4 driver leads to a high level of tissue-, stage- and sex-specific expression of the EGFP reporter in the fat body of Vg-Gal4/UAS-EGFP hybrids after blood-meal activation. In addition, the applicability of this system to study hormonal regulation of gene expression was demonstrated in in vitro organ culture experiments in which the EGFP reporter was highly activated in isolated fat bodies of previtellogenic Vg-Gal4/UAS-EGFP females incubated in the presence of 20-hydroxyecdysone (20E). Hence, this study has opened the door for further refinement of genetic tools in mosquitoes.
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Neira-Oviedo M, Tsyganov-Bodounov A, Lycett GJ, Kokoza V, Raikhel AS, Krzywinski J. The RNA-Seq approach to studying the expression of mosquito mitochondrial genes. Insect Mol Biol 2011; 20:141-152. [PMID: 20958808 DOI: 10.1111/j.1365-2583.2010.01053.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this study, we used extensive expressed sequence tag evidence obtained through 454 and Solexa next-generation sequencing to explore mtDNA transcription in male and female first instar larvae of Aedes aegypti and adults of Aedes aegypti, Anopheles gambiae, and Anopheles quadrimaculatus. Relative abundances of individual transcripts differed considerably within each sample, consistent with the differential stability of messenger RNA species. Large differences were also observed between species and between larval and adult stages; however, the male and female larval samples were remarkably similar. Quantitative PCR analysis of selected genes, cox1, l-rRNA and nd5, in larvae and adults of Ae. aegypti and in An. gambiae adults was consistent with the RNA-Seq-based quantification of expression. Finally, the absence of a conserved mtDNA region involved in transcriptional control in other dipterans suggests that mosquitoes have evolved a distinct mechanism of regulation of gene expression in the mitochondrion.
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Affiliation(s)
- M Neira-Oviedo
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, UK
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Hansen IA, Boudko DY, Shiao SH, Voronov DA, Meleshkevitch EA, Drake LL, Aguirre SE, Fox JM, Attardo GM, Raikhel AS. AaCAT1 of the yellow fever mosquito, Aedes aegypti: a novel histidine-specific amino acid transporter from the SLC7 family. J Biol Chem 2011; 286:10803-13. [PMID: 21262963 PMCID: PMC3060531 DOI: 10.1074/jbc.m110.179739] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 01/15/2011] [Indexed: 11/06/2022] Open
Abstract
Insect yolk protein precursor gene expression is regulated by nutritional and endocrine signals. A surge of amino acids in the hemolymph of blood-fed female mosquitoes activates a nutrient signaling system in the fat bodies, which subsequently derepresses yolk protein precursor genes and makes them responsive to activation by steroid hormones. Orphan transporters of the SLC7 family were identified as essential upstream components of the nutrient signaling system in the fat body of fruit flies and the yellow fever mosquito, Aedes aegypti. However, the transport function of these proteins was unknown. We report expression and functional characterization of AaCAT1, cloned from the fat body of A. aegypti. Expression of AaCAT1 transcript and protein undergoes dynamic changes during postembryonic development of the mosquito. Transcript expression was especially high in the third and fourth larval stages; however, the AaCAT1 protein was detected only in pupa and adult stages. Functional expression and analysis of AaCAT1 in Xenopus oocytes revealed that it acts as a sodium-independent cationic amino acid transporter, with unique selectivity to L-histidine at neutral pH (K(0.5)(L-His) = 0.34 ± 0.07 mM, pH 7.2). Acidification to pH 6.2 dramatically increases AaCAT1-specific His(+)-induced current. RNAi-mediated silencing of AaCAT1 reduces egg yield of subsequent ovipositions. Our data show that AaCAT1 has notable differences in its transport mechanism when compared with related mammalian cationic amino acid transporters. It may execute histidine-specific transport and signaling in mosquito tissues.
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Affiliation(s)
- Immo A Hansen
- Department of Biology and Institute of Applied Biosciences, New Mexico State University, Las Cruces, New Mexico 88003-8001, USA.
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Roy SG, Raikhel AS. The small GTPase Rheb is a key component linking amino acid signaling and TOR in the nutritional pathway that controls mosquito egg development. Insect Biochem Mol Biol 2011; 41:62-9. [PMID: 21035549 PMCID: PMC3022117 DOI: 10.1016/j.ibmb.2010.10.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 10/04/2010] [Accepted: 10/12/2010] [Indexed: 05/12/2023]
Abstract
Mosquitoes transmit numerous devastating human diseases because they require blood feeding for egg development. Previously, we have shown that the nutritional Target-of-Rapamycin (TOR) pathway mediates blood-meal activation of mosquito reproductive cycles. Blood-derived amino acid (AA) signaling through the nutrient-sensitive TOR kinase is critical for the transcriptional activation of the major yolk protein precursor (YPP) gene, vitellogenin (Vg), initiation of vitellogenesis and egg development. In this study, we provide in vitro and in vivo evidence that the Rheb GTPase (Ras Homologue Enriched in Brain), which is an upstream activator of TOR, is required for AA-mediated activation of the TOR pathway in the fat body of the mosquito Aedes aegypti. Using RNA interference (RNAi) methods, we showed that Rheb was indispensable in AA-induced phosphorylation of S6 kinase, a key downstream substrate of TOR activation. Rheb RNAi depletion resulted in significant downregulation of Vg transcription and translation in the mosquito fat body, which was monitored in vivo after blood meal or in vitro organ culture after AA stimulation. Egg development was severely hindered in mosquitoes with a Rheb RNAi depletion background. This study represents a notable step in deciphering molecular pathways controlling reproduction of this important vector of human diseases.
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Affiliation(s)
- Saurabh G. Roy
- Graduate Program in Cell, Molecular and Developmental Biology, Department of Entomology, and the Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Alexander S. Raikhel
- Corresponding author. Tel.: +1 951 827 2129; Fax: +1 951 827 2130, (A.S. Raikhel)
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36
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Bartholomay LC, Waterhouse RM, Mayhew GF, Campbell CL, Michel K, Zou Z, Ramirez JL, Das S, Alvarez K, Arensburger P, Bryant B, Chapman SB, Dong Y, Erickson SM, Karunaratne SHPP, Kokoza V, Kodira CD, Pignatelli P, Shin SW, Vanlandingham DL, Atkinson PW, Birren B, Christophides GK, Clem RJ, Hemingway J, Higgs S, Megy K, Ranson H, Zdobnov EM, Raikhel AS, Christensen BM, Dimopoulos G, Muskavitch MAT. Pathogenomics of Culex quinquefasciatus and meta-analysis of infection responses to diverse pathogens. Science 2010; 330:88-90. [PMID: 20929811 DOI: 10.1126/science.1193162] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The mosquito Culex quinquefasciatus poses a substantial threat to human and veterinary health as a primary vector of West Nile virus (WNV), the filarial worm Wuchereria bancrofti, and an avian malaria parasite. Comparative phylogenomics revealed an expanded canonical C. quinquefasciatus immune gene repertoire compared with those of Aedes aegypti and Anopheles gambiae. Transcriptomic analysis of C. quinquefasciatus genes responsive to WNV, W. bancrofti, and non-native bacteria facilitated an unprecedented meta-analysis of 25 vector-pathogen interactions involving arboviruses, filarial worms, bacteria, and malaria parasites, revealing common and distinct responses to these pathogen types in three mosquito genera. Our findings provide support for the hypothesis that mosquito-borne pathogens have evolved to evade innate immune responses in three vector mosquito species of major medical importance.
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Arensburger P, Megy K, Waterhouse RM, Abrudan J, Amedeo P, Antelo B, Bartholomay L, Bidwell S, Caler E, Camara F, Campbell CL, Campbell KS, Casola C, Castro MT, Chandramouliswaran I, Chapman SB, Christley S, Costas J, Eisenstadt E, Feschotte C, Fraser-Liggett C, Guigo R, Haas B, Hammond M, Hansson BS, Hemingway J, Hill SR, Howarth C, Ignell R, Kennedy RC, Kodira CD, Lobo NF, Mao C, Mayhew G, Michel K, Mori A, Liu N, Naveira H, Nene V, Nguyen N, Pearson MD, Pritham EJ, Puiu D, Qi Y, Ranson H, Ribeiro JMC, Roberston HM, Severson DW, Shumway M, Stanke M, Strausberg RL, Sun C, Sutton G, Tu ZJ, Tubio JMC, Unger MF, Vanlandingham DL, Vilella AJ, White O, White JR, Wondji CS, Wortman J, Zdobnov EM, Birren B, Christensen BM, Collins FH, Cornel A, Dimopoulos G, Hannick LI, Higgs S, Lanzaro GC, Lawson D, Lee NH, Muskavitch MAT, Raikhel AS, Atkinson PW. Sequencing of Culex quinquefasciatus establishes a platform for mosquito comparative genomics. Science 2010; 330:86-8. [PMID: 20929810 DOI: 10.1126/science.1191864] [Citation(s) in RCA: 343] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Culex quinquefasciatus (the southern house mosquito) is an important mosquito vector of viruses such as West Nile virus and St. Louis encephalitis virus, as well as of nematodes that cause lymphatic filariasis. C. quinquefasciatus is one species within the Culex pipiens species complex and can be found throughout tropical and temperate climates of the world. The ability of C. quinquefasciatus to take blood meals from birds, livestock, and humans contributes to its ability to vector pathogens between species. Here, we describe the genomic sequence of C. quinquefasciatus: Its repertoire of 18,883 protein-coding genes is 22% larger than that of Aedes aegypti and 52% larger than that of Anopheles gambiae with multiple gene-family expansions, including olfactory and gustatory receptors, salivary gland genes, and genes associated with xenobiotic detoxification.
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Affiliation(s)
- Peter Arensburger
- Center for Disease Vector Research, University of California Riverside, Riverside, CA 92521, USA.
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Antonova Y, Alvarez KS, Kim YJ, Kokoza V, Raikhel AS. The role of NF-kappaB factor REL2 in the Aedes aegypti immune response. Insect Biochem Mol Biol 2009; 39:303-14. [PMID: 19552893 PMCID: PMC2702699 DOI: 10.1016/j.ibmb.2009.01.007] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2008] [Revised: 01/07/2009] [Accepted: 01/13/2009] [Indexed: 05/15/2023]
Abstract
Mosquitoes transmit numerous diseases that continue to be an enormous burden on public health worldwide. Transgenic mosquitoes impervious to vector-borne pathogens, in concert with vector control and drug and vaccine development, comprise an arsenal of means anticipated to defeat mosquito-spread diseases in the future. Mosquito transgenesis allows tissue-specific manipulation of their major immune pathways and enhances the ability to study mosquito-pathogen interactions. Here, we report the generation of two independent transgenic strains of Aedes aegypti overexpressing the NF-?B transcriptional factor REL2, a homologue of Drosophila Relish, which is shown to be under the control of the vitellogenin promoter in the mosquito fat body after a blood meal. We show that this REL2 overexpression in the fat body results in transcriptional activation of Defensins A, C, and D, and Cecropins A and N, as well as translation and secretion of Defensin A protein into the hemolymph. We also demonstrate that induction of REL2 results in the increased resistance of the mosquito to tested Gram-negative and Gram-positive bacteria. Importantly, induction of transgenic REL2 leads to the significant decrease in susceptibility of A. aegypti to Plasmodium gallinaceum infection. Consistently, RNAi knockdown of REL2 in wild-type mosquitoes results in a delay in Defensin A and Cecropin A expression in response to infection and in increased susceptibility to both bacteria and P. gallinaceum. Moreover, our transgenic assays demonstrate that the N-terminus of the mosquito REL2, which includes the His/Gln-rich and serine-rich regions, plays a role in its transactivation properties.
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Affiliation(s)
- Yevgeniya Antonova
- Graduate Program in Biochemistry and Molecular Biology, University of California, Riverside, CA 92521, USA
| | - Kanwal S. Alvarez
- Graduate Program in Cell, Molecular and Developmental Biology, University of California, Riverside, CA 92521, USA
| | | | - Vladimir Kokoza
- Department of Entomology, and the Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Alexander S. Raikhel
- Department of Entomology, and the Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
- Author for correspondence: Alexander S. Raikhel, Department of Entomology, University of California, Riverside, Watkins Drive, CA 92521; Tel. 951-827-2129, Fax. 951 827-2130; E-mail address:
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Mishra SK, Jha A, Steinhauser AL, Kokoza VA, Washabaugh CH, Raikhel AS, Foster WA, Traub LM. Internalization of LDL-receptor superfamily yolk-protein receptors during mosquito oogenesis involves transcriptional regulation of PTB-domain adaptors. J Cell Sci 2008; 121:1264-74. [DOI: 10.1242/jcs.025833] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
In the anautogenous disease vector mosquitoes Anopheles gambiae and Aedes aegypti, egg development is nutritionally controlled. A blood meal permits further maturation of developmentally repressed previtellogenic egg chambers. This entails massive storage of extraovarian yolk precursors by the oocyte, which occurs through a burst of clathrin-mediated endocytosis. Yolk precursors are concentrated at clathrin-coated structures on the oolemma by two endocytic receptors, the vitellogenin and lipophorin receptors. Both these mosquito receptors are members of the low-density-lipoprotein-receptor superfamily that contain FxNPxY-type internalization signals. In mammals, this tyrosine-based signal is not decoded by the endocytic AP-2 adaptor complex directly. Instead, two functionally redundant phosphotyrosine-binding domain adaptors, Disabled 2 and the autosomal recessive hypercholesterolemia protein (ARH) manage the internalization of the FxNPxY sorting signal. Here, we report that a mosquito ARH-like protein, which we designate trephin, possess similar functional properties to the orthologous vertebrate proteins despite engaging AP-2 in an atypical manner, and that mRNA expression in the egg chamber is strongly upregulated shortly following a blood meal. Temporally regulated trephin transcription and translation suggests a mechanism for controlling yolk uptake when vitellogenin and lipophorin receptors are expressed and clathrin coats operate in previtellogenic ovaries.
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Affiliation(s)
- Sanjay K. Mishra
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Anupma Jha
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Amie L. Steinhauser
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Vladimir A. Kokoza
- Department of Entomology, University of California, Riverside, CA 92521, USA
| | - Charles H. Washabaugh
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | | | | | - Linton M. Traub
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Bian G, Raikhel AS, Zhu J. Characterization of a juvenile hormone-regulated chymotrypsin-like serine protease gene in Aedes aegypti mosquito. Insect Biochem Mol Biol 2008; 38:190-200. [PMID: 18207080 PMCID: PMC2253661 DOI: 10.1016/j.ibmb.2007.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Revised: 10/28/2007] [Accepted: 10/29/2007] [Indexed: 05/15/2023]
Abstract
After female mosquitoes ingest blood from vertebrate hosts, exopeptidases and endopeptidases are required for digesting blood proteins in the midgut into amino acids, which female mosquitoes use to build yolk proteins. These proteases are not always present in the midgut, and their diverse expression patterns suggest that production of these enzymes is highly regulated in order to meet specific physiological demands at various stages. Here we report identification of a serine-type protease, JHA15, in the yellow fever mosquito Aedes aegypti. This protein shares high sequence homology with chymotrypsins, and indeed exhibits specific chymotrypsin enzymatic activity. The JHA15 gene is expressed primarily in the midgut of adult female mosquitoes. Our results indicate that its transcription is activated by juvenile hormone in the newly emerged female adults. Although its mRNA profile is similar to that of the early trypsin gene, we found that JHA15 proteins were readily detected in the midgut epithelium cells of both non-blood-fed and blood-fed mosquitoes. Analysis of polysomal RNA further substantiated that synthesis of JHA15 occurs before and shortly after blood feeding. Knocking down expression of JHA15 resulted in no evident phenotypic changes, implying that functional redundancy exists among those proteolytic enzymes.
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Affiliation(s)
- Guowu Bian
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Alexander S Raikhel
- Department of Entomology, University of California, Riverside, CA 92521, USA
| | - Jinsong Zhu
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Corresponding author. Tel.: +1 540 231 3841; fax: +1 540 231 9070;
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Shiao SH, Hansen IA, Zhu J, Sieglaff DH, Raikhel AS. Juvenile hormone connects larval nutrition with target of rapamycin signaling in the mosquito Aedes aegypti. J Insect Physiol 2008; 54:231-9. [PMID: 17981294 PMCID: PMC2242809 DOI: 10.1016/j.jinsphys.2007.09.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Revised: 09/20/2007] [Accepted: 09/24/2007] [Indexed: 05/11/2023]
Abstract
Anautogenous mosquitoes require blood meals to promote egg development. If adequate nutrients are not obtained during larval development, the resulting "small" sized adult mosquitoes require multiple blood meals for egg development; markedly increasing host-vector contacts and the likelihood of disease transmission. Nutrient-sensitive target of rapamycin (TOR) signaling is a key signaling pathway that links elevated hemolymph amino acid levels derived from the blood meal to the expression of yolk protein precursors in the fat body. Here we report that the blood-meal-induced activation of the TOR-signaling pathway and subsequent egg maturation depends on the accumulation of adequate nutritional reserves during larval development. We have established well-nourished, "standard" mosquitoes and malnourished, "small" mosquitoes as models to address this nutrient sensitive pathway. This regulatory mechanism involves juvenile hormone (JH), which acts as a mediator of fat body competence, permitting the response to amino acids derived from the blood meal. We demonstrate that treatment with JH results in recovery of the TOR molecular machinery, Aedes aegypti cationic amino acid transporter 2 (AaiCAT2), TOR, and S6 kinase (S6K), in fat bodies of small mosquitoes, enabling them to complete their first gonotrophic cycle after a single blood meal. These findings establish a direct link between nutrient reserves and the establishment of TOR signaling in mosquitoes.
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Affiliation(s)
| | | | | | | | - Alexander S. Raikhel
- *Corresponding author Department of Entomology, University of California, Riverside, Watkins Drive, CA 92521; Tel. 951-827-2146, Fax. 951 827-2130; E-mail:
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Roy SG, Hansen IA, Raikhel AS. Effect of insulin and 20-hydroxyecdysone in the fat body of the yellow fever mosquito, Aedes aegypti. Insect Biochem Mol Biol 2007; 37:1317-26. [PMID: 17967350 PMCID: PMC2104489 DOI: 10.1016/j.ibmb.2007.08.004] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 08/20/2007] [Accepted: 08/22/2007] [Indexed: 05/12/2023]
Abstract
In mosquitoes, yolk protein precursor (YPP) gene expression is activated after a blood meal through the synergistic action of a steroid hormone and the amino acid/target of rapamycin (TOR) signaling pathway in the fat body. We investigated the role of insulin signaling in the regulation of YPP gene expression. The presence of mosquito insulin receptor (InR) and the Protein kinase B (PKB/Akt) in the adult fat body of female mosquitoes was confirmed by means of the RNA interference (RNAi). Fat bodies stimulated with insulin were able to promote the phosphorylation of ribosomal S6 Kinase, a key protein of the TOR signaling pathway. Importantly, insulin in combination with 20-hydroxyecdysone activated transcription of the YPP gene vitellogenin (Vg), and this process was sensitive to the phosphoinositide-3 kinase (PI-3k) inhibitor LY294002 as well as the TOR inhibitor rapamycin. RNAi-mediated knockdown of the mosquito InR, Akt, and TOR inhibited insulin-induced Vg gene expression as well as S6 Kinase phosphorylation in in vitro fat body culture assays.
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Affiliation(s)
- Saurabh G. Roy
- Graduate Program in Cell, Molecular and Developmental Biology, University of California, Riverside, CA 92521
| | - Immo A. Hansen
- Department of Entomology, and the Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Alexander S. Raikhel
- Department of Entomology, and the Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
- Corresponding author. Tel.: +1 951 827 2129; Fax: +1 951 827 2130, E-mail address: (A.S. Raikhel)
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Hansen IA, Sieglaff DH, Munro JB, Shiao SH, Cruz J, Lee IW, Heraty JM, Raikhel AS. Forkhead transcription factors regulate mosquito reproduction. Insect Biochem Mol Biol 2007; 37:985-97. [PMID: 17681238 PMCID: PMC2441594 DOI: 10.1016/j.ibmb.2007.05.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2007] [Revised: 05/04/2007] [Accepted: 05/09/2007] [Indexed: 05/16/2023]
Abstract
Forkhead-box (Fox) genes encode a family of transcription factors defined by a 'winged helix' DNA-binding domain. In this study we aimed to identify Fox factors that are expressed within the fat body of the yellow fever mosquito Aedes aegypti, and determine whether any of these are involved in the regulation of mosquito yolk protein gene expression. The Ae. aegypti genome contains 18 loci that encode putative Fox factors. Our stringent cladistic analysis has profound implications for the use of Fox genes as phylogenetic markers. Twelve Ae. aegypti Fox genes are expressed within various tissues of adult females, six of which are expressed within the fat body. All six Fox genes expressed in the fat body displayed dynamic expression profiles following a blood meal. We knocked down the 'fat body Foxes' through RNAi to determine whether these 'knockdowns' hindered amino acid-induced vitellogenin gene expression. We also determined the effect of these knockdowns on the number of eggs deposited following a blood meal. Knockdown of FoxN1, FoxN2, FoxL, and FoxO, had a negative effect on amino acid-induced vitellogenin gene expression and resulted in significantly fewer eggs laid. Our analysis stresses the importance of Fox transcription factors in regulating mosquito reproduction.
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Affiliation(s)
| | | | | | | | | | | | | | - Alexander S. Raikhel
- * Address correspondence to: Alexander S. Raikhel, Department of Entomology, University of California, Riverside, Watkins Drive, CA 92521; Tel. 951-827-2146, Fax. 951 827-2140; E.mail:
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Nene V, Wortman JR, Lawson D, Haas B, Kodira C, Tu ZJ, Loftus B, Xi Z, Megy K, Grabherr M, Ren Q, Zdobnov EM, Lobo NF, Campbell KS, Brown SE, Bonaldo MF, Zhu J, Sinkins SP, Hogenkamp DG, Amedeo P, Arensburger P, Atkinson PW, Bidwell S, Biedler J, Birney E, Bruggner RV, Costas J, Coy MR, Crabtree J, Crawford M, Debruyn B, Decaprio D, Eiglmeier K, Eisenstadt E, El-Dorry H, Gelbart WM, Gomes SL, Hammond M, Hannick LI, Hogan JR, Holmes MH, Jaffe D, Johnston JS, Kennedy RC, Koo H, Kravitz S, Kriventseva EV, Kulp D, Labutti K, Lee E, Li S, Lovin DD, Mao C, Mauceli E, Menck CFM, Miller JR, Montgomery P, Mori A, Nascimento AL, Naveira HF, Nusbaum C, O'leary S, Orvis J, Pertea M, Quesneville H, Reidenbach KR, Rogers YH, Roth CW, Schneider JR, Schatz M, Shumway M, Stanke M, Stinson EO, Tubio JMC, Vanzee JP, Verjovski-Almeida S, Werner D, White O, Wyder S, Zeng Q, Zhao Q, Zhao Y, Hill CA, Raikhel AS, Soares MB, Knudson DL, Lee NH, Galagan J, Salzberg SL, Paulsen IT, Dimopoulos G, Collins FH, Birren B, Fraser-Liggett CM, Severson DW. Genome sequence of Aedes aegypti, a major arbovirus vector. Science 2007; 316:1718-23. [PMID: 17510324 PMCID: PMC2868357 DOI: 10.1126/science.1138878] [Citation(s) in RCA: 820] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We present a draft sequence of the genome of Aedes aegypti, the primary vector for yellow fever and dengue fever, which at approximately 1376 million base pairs is about 5 times the size of the genome of the malaria vector Anopheles gambiae. Nearly 50% of the Ae. aegypti genome consists of transposable elements. These contribute to a factor of approximately 4 to 6 increase in average gene length and in sizes of intergenic regions relative to An. gambiae and Drosophila melanogaster. Nonetheless, chromosomal synteny is generally maintained among all three insects, although conservation of orthologous gene order is higher (by a factor of approximately 2) between the mosquito species than between either of them and the fruit fly. An increase in genes encoding odorant binding, cytochrome P450, and cuticle domains relative to An. gambiae suggests that members of these protein families underpin some of the biological differences between the two mosquito species.
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Affiliation(s)
- Vishvanath Nene
- Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA.
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Waterhouse RM, Kriventseva EV, Meister S, Xi Z, Alvarez KS, Bartholomay LC, Barillas-Mury C, Bian G, Blandin S, Christensen BM, Dong Y, Jiang H, Kanost MR, Koutsos AC, Levashina EA, Li J, Ligoxygakis P, Maccallum RM, Mayhew GF, Mendes A, Michel K, Osta MA, Paskewitz S, Shin SW, Vlachou D, Wang L, Wei W, Zheng L, Zou Z, Severson DW, Raikhel AS, Kafatos FC, Dimopoulos G, Zdobnov EM, Christophides GK. Evolutionary dynamics of immune-related genes and pathways in disease-vector mosquitoes. Science 2007; 316:1738-43. [PMID: 17588928 PMCID: PMC2042107 DOI: 10.1126/science.1139862] [Citation(s) in RCA: 451] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mosquitoes are vectors of parasitic and viral diseases of immense importance for public health. The acquisition of the genome sequence of the yellow fever and Dengue vector, Aedes aegypti (Aa), has enabled a comparative phylogenomic analysis of the insect immune repertoire: in Aa, the malaria vector Anopheles gambiae (Ag), and the fruit fly Drosophila melanogaster (Dm). Analysis of immune signaling pathways and response modules reveals both conservative and rapidly evolving features associated with different functional gene categories and particular aspects of immune reactions. These dynamics reflect in part continuous readjustment between accommodation and rejection of pathogens and suggest how innate immunity may have evolved.
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Affiliation(s)
- Robert M Waterhouse
- Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
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Zhu J, Chen L, Raikhel AS. Distinct roles of Broad isoforms in regulation of the 20-hydroxyecdysone effector gene, Vitellogenin, in the mosquito Aedes aegypti. Mol Cell Endocrinol 2007; 267:97-105. [PMID: 17303321 PMCID: PMC1929017 DOI: 10.1016/j.mce.2007.01.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Accepted: 01/05/2007] [Indexed: 10/23/2022]
Abstract
We investigated the role of the mosquito broad (br) gene in regulating the 20-hydroxyecdysone (20E) effector Vitellogenin (Vg) gene. Injection of double-stranded RNA corresponding to the BR isoform Z2 led to a significant decrease in expression of the Vg gene at 8 and 24h post-blood meal. Knockdown of Z1 or Z4 resulted in enhanced Vg expression beyond its normal expression time. In vitro studies suggested that the effects of BR require its direct binding to the Vg promoter, as well as protein-protein interaction between BR and the ecdysone receptor complex. The BR isoforms are therefore essential for a proper stage-specific biological response to 20E in the adult female mosquito. In particular, the isoform Z2 is required for 20E-mediated activation of Vg, while isoforms Z1 and Z4 serve as repressors to ensure appropriate termination of Vg expression.
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Affiliation(s)
- Jinsong Zhu
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
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Zhu J, Chen L, Sun G, Raikhel AS. The competence factor beta Ftz-F1 potentiates ecdysone receptor activity via recruiting a p160/SRC coactivator. Mol Cell Biol 2006; 26:9402-12. [PMID: 17015464 PMCID: PMC1698532 DOI: 10.1128/mcb.01318-06] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 08/22/2006] [Accepted: 09/21/2006] [Indexed: 11/20/2022] Open
Abstract
Hormones provide generalized signals that are interpreted in a specific spatial and temporal manner by a developing or reproducing multicellular organism. The ability to respond to hormones is determined by the competence of a cell or a tissue. The betaFtz-F1 orphan nuclear receptor acts as a competence factor for the steroid hormone 20-hydroxyecdysone (20E) in Drosophila melanogaster metamorphosis and mosquito reproduction. The molecular nature of the betaFtz-F1 action remains unclear. We report that the protein-protein interaction between betaFtz-F1 and a p160/SRC coactivator of the ecdysone receptor, FISC, is crucial for the stage-specific expression of the 20E effector genes during mosquito reproduction. This interaction dramatically increases recruitment of FISC to the functional ecdysone receptor in a 20E-dependent manner. The presence of betaFtz-F1 facilitates loading of FISC and the ecdysone receptor on the target promoters, leading to enhanced local histone H4 acetylation and robust activation of the target genes. Thus, our results reveal the molecular basis of competence for the stage-specific 20E response.
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Affiliation(s)
- Jinsong Zhu
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
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Shin SW, Bian G, Raikhel AS. A Toll Receptor and a Cytokine, Toll5A and Spz1C, Are Involved in Toll Antifungal Immune Signaling in the Mosquito Aedes aegypti. J Biol Chem 2006; 281:39388-95. [PMID: 17068331 DOI: 10.1074/jbc.m608912200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The fungal-specific immune response in the mosquito Aedes aegypti involves the Toll immune pathway transduced through REL1, a homologue of the NF-kappaB transcription factor Drosophila Dorsal. The Toll receptor and its ligand, Spätzle (Spz), link extracellular immune signals to the Toll intracellular transduction pathway. Five homologues to the Drosophila Toll (Toll1) receptor (Toll1A, Toll1B, Toll5A, Toll5B, and Toll4) and three homologues to the Drosophila cytokine Spätzle (Spz1A, 1B, and 1C) were identified from genomic and cDNA sequence data bases. Toll1A, Toll5A, Toll5B, and Spz1A were specifically induced in the mosquito fat body following fungal challenge. This transcriptional up-regulation was mediated by REL1. Spz1C was constitutively expressed in the mosquito fat body, whereas Spz1B and Toll4 were primarily expressed in ovarian tissues of female mosquitoes. The transcripts of Toll1B were only detected in early stages of mosquito embryos. RNA interference knock down of Toll5A and Spz1C resulted in two phenotypes of Aedes Toll/REL1 pathway deficiency: decreased induction of Aedes Serpin-27A following fungal challenge and increased susceptibility to the entomopathogenic fungus Beauveria bassiana. These data suggest that Toll5A and Spz1C function as cytokine receptor systems specific to the Toll receptor-mediated immune response following fungal challenge in the mosquito fat body.
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Affiliation(s)
- Sang Woon Shin
- Department of Entomology and the Institute for Integrative Genome Biology, University of California, Riverside, California 92521, USA
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Attardo GM, Hansen IA, Shiao SH, Raikhel AS. Identification of two cationic amino acid transporters required for nutritional signaling during mosquito reproduction. ACTA ACUST UNITED AC 2006; 209:3071-8. [PMID: 16888056 DOI: 10.1242/jeb.02349] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The defining characteristic of anautogenous mosquitoes is their requirement for a blood meal to initiate reproduction. The need for blood drives the association of vector and host, and is the primary reason why anautogenous mosquitoes are effective disease vectors. During mosquito vitellogenesis, a key process in reproduction, yolk protein precursor (YPP) gene expression is activated specifically in the fat body, the insect analogue of the vertebrate liver. We have demonstrated that blood meal derived amino acids (AAs) activate YPP genes via the target of rapamycin (TOR)-signal transduction pathway. Here we show, by stimulating fat bodies with balanced AA solutions lacking individual AAs, that specific cationic and branched AAs are essential for activation of the vitellogenin (vg) gene, the major YPP gene. Treatment of fat bodies with AA uptake inhibitors results in a strong inhibition of AA-induced vg gene expression proving that an active transport mechanism is necessary to transduce the AA signal. We identified two cationic AA transporters (CATs) in the fat body of Aedes aegypti females--Aa slimfast and iCAT2. RNAi knockdown of slimfast and iCAT2 results in a strong decrease in the response to AAs by the vg gene similar to that seen due to TOR inhibition. These data demonstrate that active uptake of specific AAs plays a key role in nutritional signaling during the onset of vitellogenic gene expression in mosquitoes and it is mediated by two cationic AA transporters.
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Affiliation(s)
- Geoffrey M Attardo
- Center for Disease-Vector Research, Department of Entomology and the Institute for Integrative Genome Biology, University of California Riverside, 3401 Watkins Drive, Riverside, CA-92521, USA
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