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Hu W, Wang Y, Chen X, Huang J, Kuang J, Wang L, Mao K, Dou L. Genome assembly of an endemic butterfly (Minois Aurata) shed light on the genetic mechanisms underlying ecological adaptation to arid valley habitat. BMC Genomics 2024; 25:1134. [PMID: 39580397 PMCID: PMC11585952 DOI: 10.1186/s12864-024-11058-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2024] [Accepted: 11/15/2024] [Indexed: 11/25/2024] Open
Abstract
BACKGROUND The Hengduan Mountains, one of the global biodiversity hotspots with exceptional species richness and high endemism, contains numerous arid valleys that create a distinctive geographical and ecological landscape. However, the adaptive evolutionary mechanisms of organism in the arid valley remain poorly understood. Minois aurata, an endemic butterfly species found exclusively in the arid valley of the upper Minjiang River, represents an attractive model system for studying adaptive evolutionary mechanisms to arid valley environments. RESULTS Here, we present the first chromosome-level genome assembly for Minois aurata, with a total size of approximately 609.17 Mb, and a scaffold N50 size of 23.88 Mb. These scaffolds were further clustered and anchored onto 29 chromosomes based on Hi-C data. A total of 16,163 protein-coding genes were predicted, of which 91.83% were functionally annotated. The expansion of transposable elements (TEs) accounts for the relatively large genome size of M. aurata, potentially aiding its adaptation to environmental conditions. Phylogenomic analyses based on 3,785 single-copy genes revealed that M. aurata is most closely related to Hipparchia semele. Further mitochondrial genome analysis of four Minois species placed M. aurata in a basal position within the genus, supporting it as an independent species. A total of 185 rapidly evolving and 232 specific gene families were identified in M. aurata. Functional enrichment analysis indicated that these gene families were mainly associated with ultraviolet radiation, heat and hypoxia responses. We also identified 234 positive selected genes in M. aurata, some of which are related to compound eye photoreceptor development, osmotic stress, and light stimulus response. Demographic analysis indicated that the effective population size of M. aurata decreased around 0.4 and 0.04 million years ago, respectively, coinciding with the localized sub-glaciation. CONCLUSION The chromosome-level genome offers a comprehensive genomic basis for understanding the evolutionary and adaptive strategies of Minois aurata in the unique arid valley environment of the Hengduan Mountains, while also providing valuable insights into the broader mechanisms of organism adaptation to such habitats.
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Affiliation(s)
- Wenqian Hu
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610065, P. R. China
| | - Yi Wang
- Sichuan Key Laboratory of Ecological Restoration and Conservation for Forest and Wetland, Sichuan Academy of Forestry, Chengdu, 610081, China
| | - Xiaoxiao Chen
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610065, P. R. China
| | - Jialong Huang
- Fujian Key Laboratory on Conservation and Sustainable Utilization of Marine Biodiversity, Fuzhou Institute of Oceanography, College of Geography and Oceanography, Minjiang University, Fuzhou, 350108, China
| | - Jingge Kuang
- Ministry of Education Key Laboratory for Transboundary Ecosecurity of Southwest China, Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology and Centre for Invasion Biology, Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming, 650504, Yunnan, China
| | - Lei Wang
- Institute of Plant Protection, Sichuan Academy of Agricultural Sciences, Chengdu, China
| | - Kangshan Mao
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610065, P. R. China.
| | - Liang Dou
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610065, P. R. China.
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Tabuloc CA, Carlson CR, Ganjisaffar F, Truong CC, Chen CH, Lewald KM, Hidalgo S, Nicola NL, Jones CE, Sial AA, Zalom FG, Chiu JC. Transcriptome analysis of Drosophila suzukii reveals molecular mechanisms conferring pyrethroid and spinosad resistance. Sci Rep 2024; 14:19867. [PMID: 39191909 PMCID: PMC11349914 DOI: 10.1038/s41598-024-70037-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 08/09/2024] [Indexed: 08/29/2024] Open
Abstract
Drosophila suzukii lay eggs in soft-skinned, ripening fruits, making this insect a serious threat to berry production. Since its 2008 introduction into North America, growers have used insecticides, such as pyrethroids and spinosads, as the primary approach for D. suzukii management, resulting in development of insecticide resistance in this pest. This study sought to identify the molecular mechanisms conferring insecticide resistance in these populations. We sequenced the transcriptomes of two pyrethroid- and two spinosad-resistant isofemale lines. In both pyrethroid-resistant lines and one spinosad-resistant line, we identified overexpression of metabolic genes that are implicated in resistance in other insect pests. In the other spinosad-resistant line, we observed an overexpression of cuticular genes that have been linked to resistance. Our findings enabled the development of molecular diagnostics that we used to confirm persistence of insecticide resistance in California, U.S.A. To validate these findings, we leveraged D. melanogaster mutants with reduced expression of metabolic or cuticular genes that were found to be upregulated in resistant D. suzukii to demonstrate that these genes are involved in promoting resistance. This study is the first to characterize the molecular mechanisms of insecticide resistance in D. suzukii and provides insights into how current management practices can be optimized.
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Affiliation(s)
- Christine A Tabuloc
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, California, USA
| | - Curtis R Carlson
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, California, USA
| | - Fatemeh Ganjisaffar
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, California, USA
| | - Cindy C Truong
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, California, USA
| | - Ching-Hsuan Chen
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, California, USA
| | - Kyle M Lewald
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, California, USA
| | - Sergio Hidalgo
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, California, USA
| | - Nicole L Nicola
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, California, USA
| | - Cera E Jones
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - Ashfaq A Sial
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - Frank G Zalom
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, California, USA
| | - Joanna C Chiu
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, California, USA.
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3
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Hannon CE, Eisen MB. Intrinsic protein disorder is insufficient to drive subnuclear clustering in embryonic transcription factors. eLife 2024; 12:RP88221. [PMID: 38275292 PMCID: PMC10945700 DOI: 10.7554/elife.88221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024] Open
Abstract
Modern microscopy has revealed that core nuclear functions, including transcription, replication, and heterochromatin formation, occur in spatially restricted clusters. Previous work from our lab has shown that subnuclear high-concentration clusters of transcription factors may play a role in regulating RNA synthesis in the early Drosophila embryo. A nearly ubiquitous feature of eukaryotic transcription factors is that they contain intrinsically disordered regions (IDRs) that often arise from low complexity amino acid sequences within the protein. It has been proposed that IDRs within transcription factors drive co-localization of transcriptional machinery and target genes into high-concentration clusters within nuclei. Here, we test that hypothesis directly, by conducting a broad survey of the subnuclear localization of IDRs derived from transcription factors. Using a novel algorithm to identify IDRs in the Drosophila proteome, we generated a library of IDRs from transcription factors expressed in the early Drosophila embryo. We used this library to perform a high-throughput imaging screen in Drosophila Schneider-2 (S2) cells. We found that while subnuclear clustering does not occur when the majority of IDRs are expressed alone, it is frequently seen in full-length transcription factors. These results are consistent in live Drosophila embryos, suggesting that IDRs are insufficient to drive the subnuclear clustering behavior of transcription factors. Furthermore, the clustering of transcription factors in living embryos was unaffected by the deletion of IDR sequences. Our results demonstrate that IDRs are unlikely to be the primary molecular drivers of the clustering observed during transcription, suggesting a more complex and nuanced role for these disordered protein sequences.
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Affiliation(s)
- Colleen E Hannon
- Howard Hughes Medical Institute, University of CaliforniaBerkeleyUnited States
| | - Michael B Eisen
- Howard Hughes Medical Institute, University of CaliforniaBerkeleyUnited States
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4
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Fuhrmann N, Prakash C, Kaiser TS. Polygenic adaptation from standing genetic variation allows rapid ecotype formation. eLife 2023; 12:e82824. [PMID: 36852484 PMCID: PMC9977305 DOI: 10.7554/elife.82824] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 02/07/2023] [Indexed: 03/01/2023] Open
Abstract
Adaptive ecotype formation can be the first step to speciation, but the genetic underpinnings of this process are poorly understood. Marine midges of the genus Clunio (Diptera) have recolonized Northern European shore areas after the last glaciation. In response to local tide conditions they have formed different ecotypes with respect to timing of adult emergence, oviposition behavior and larval habitat. Genomic analysis confirms the recent establishment of these ecotypes, reflected in massive haplotype sharing between ecotypes, irrespective of whether there is ongoing gene flow or geographic isolation. QTL mapping and genome screens reveal patterns of polygenic adaptation from standing genetic variation. Ecotype-associated loci prominently include circadian clock genes, as well as genes affecting sensory perception and nervous system development, hinting to a central role of these processes in ecotype formation. Our data show that adaptive ecotype formation can occur rapidly, with ongoing gene flow and largely based on a re-assortment of existing alleles.
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Affiliation(s)
- Nico Fuhrmann
- Max Planck Institute for Evolutionary BiologyPlönGermany
| | - Celine Prakash
- Max Planck Institute for Evolutionary BiologyPlönGermany
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5
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Watase GJ, Nelson JO, Yamashita YM. Nonrandom sister chromatid segregation mediates rDNA copy number maintenance in Drosophila. SCIENCE ADVANCES 2022; 8:eabo4443. [PMID: 35895823 PMCID: PMC9328678 DOI: 10.1126/sciadv.abo4443] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
Although considered to be exact copies of each other, sister chromatids can segregate nonrandomly in some cases. For example, sister chromatids of the X and Y chromosomes segregate nonrandomly during asymmetric division of male germline stem cells (GSCs) in Drosophila melanogaster. Here, we demonstrate that the ribosomal DNA (rDNA) loci, which are located on the X and Y chromosomes, and an rDNA binding protein Indra are required for nonrandom sister chromatid segregation (NRSS). We provide the evidence that NRSS, following unequal sister chromatid exchange, is a mechanism by which GSCs recover rDNA copy number, counteracting the spontaneous copy number loss that occurs during aging. Our study reveals an unexpected role for NRSS in maintaining germline immortality through maintenance of a vulnerable genomic element, rDNA.
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Affiliation(s)
- George J. Watase
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, 455 Main Street, Cambridge, MA 02142, USA
| | - Jonathan O. Nelson
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, 455 Main Street, Cambridge, MA 02142, USA
| | - Yukiko M. Yamashita
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, 455 Main Street, Cambridge, MA 02142, USA
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6
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Marchiano F, Haering M, Habermann BH. OUP accepted manuscript. Nucleic Acids Res 2022; 50:W490-W499. [PMID: 35524562 PMCID: PMC9252804 DOI: 10.1093/nar/gkac306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/09/2022] [Accepted: 04/15/2022] [Indexed: 11/13/2022] Open
Abstract
Mitochondria are subcellular organelles present in almost all eukaryotic cells, which play a central role in cellular metabolism. Different tissues, health and age conditions are characterized by a difference in mitochondrial structure and composition. The visual data mining platform mitoXplorer 1.0 was developed to explore the expression dynamics of genes associated with mitochondrial functions that could help explain these differences. It, however, lacked functions aimed at integrating mitochondria in the cellular context and thus identifying regulators that help mitochondria adapt to cellular needs. To fill this gap, we upgraded the mitoXplorer platform to version 2.0 (mitoXplorer 2.0). In this upgrade, we implemented two novel integrative functions, network analysis and transcription factor enrichment, to specifically help identify signalling or transcriptional regulators of mitochondrial processes. In addition, we implemented several other novel functions to allow the platform to go beyond simple data visualization, such as an enrichment function for mitochondrial processes, a function to explore time-series data, the possibility to compare datasets across species and an IDconverter to help facilitate data upload. We demonstrate the usefulness of these functions in three specific use cases. mitoXplorer 2.0 is freely available without login at http://mitoxplorer2.ibdm.univ-mrs.fr.
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Affiliation(s)
- Fabio Marchiano
- Aix-Marseille University, CNRS, IBDM UMR 7288, 13009 Marseille, France
| | - Margaux Haering
- Aix-Marseille University, CNRS, IBDM UMR 7288, 13009 Marseille, France
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He L, Chen IW, Zhang Z, Zheng W, Sayadi A, Wang L, Sang W, Ji R, Lei J, Arnqvist G, Lei C, Zhu-Salzman K. In silico promoter analysis and functional validation identify CmZFH, the co-regulator of hypoxia-responsive genes CmScylla and CmLPCAT. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2022; 140:103681. [PMID: 34800642 DOI: 10.1016/j.ibmb.2021.103681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/30/2021] [Accepted: 11/06/2021] [Indexed: 06/13/2023]
Abstract
Oxygen (O2) plays an essential role in aerobic organisms including terrestrial insects. Under hypoxic stress, the cowpea bruchid (Callosobruchus maculatus) ceases feeding and growth. However, larvae, particularly 4th instar larvae exhibit very high tolerance to hypoxia and can recover normal growth once brought to normoxia. To better understand the molecular mechanism that enables insects to cope with low O2 stress, we performed RNA-seq to distinguish hypoxia-responsive genes in midguts and subsequently identified potential common cis-elements in promoters of hypoxia-induced and -repressed genes, respectively. Selected elements were subjected to gel-shift and transient transfection assays to confirm their cis-regulatory function. Of these putative common cis-elements, AREB6 appeared to regulate the expression of CmLPCAT and CmScylla, two hypoxia-induced genes. CmZFH, the putative AREB6-binding protein, was hypoxia-inducible. Transient expression of CmZFH in Drosophila S2 cells activated CmLPCAT and CmScylla, and their induction was likely through interaction of CmZFH with AREB6. Binding to AREB6 was further confirmed by bacterially expressed CmZFH recombinant protein. Deletion analyses indicated that the N-terminal zinc-finger cluster of CmZFH was the key AREB6-binding domain. Through in silico and experimental exploration, we discovered novel transcriptional regulatory components associated with gene expression dynamics under hypoxia that facilitated insect survival.
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Affiliation(s)
- Li He
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China; Department of Entomology, Texas A&M University, College Station, TX, 77843, USA; Institute for Plant Genomics & Biotechnology, Texas A&M University, College Station, TX, 77843, USA
| | - Ivy W Chen
- Department of Entomology, Texas A&M University, College Station, TX, 77843, USA; Institute for Plant Genomics & Biotechnology, Texas A&M University, College Station, TX, 77843, USA
| | - Zan Zhang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Academy of Agricultural Sciences, Southwest University, Chongqing, 400716, China
| | - Wenping Zheng
- Key Laboratory of Horticultural Plant Biology (MOE), Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ahmed Sayadi
- Animal Ecology, Department of Ecology and Genetics, Uppsala University, Uppsala, 75236, Sweden
| | - Lei Wang
- Department of Entomology, Texas A&M University, College Station, TX, 77843, USA; Institute for Plant Genomics & Biotechnology, Texas A&M University, College Station, TX, 77843, USA
| | - Wen Sang
- Department of Entomology, Texas A&M University, College Station, TX, 77843, USA; Institute for Plant Genomics & Biotechnology, Texas A&M University, College Station, TX, 77843, USA
| | - Rui Ji
- Department of Entomology, Texas A&M University, College Station, TX, 77843, USA; Institute for Plant Genomics & Biotechnology, Texas A&M University, College Station, TX, 77843, USA
| | - Jiaxin Lei
- Department of Entomology, Texas A&M University, College Station, TX, 77843, USA; Institute for Plant Genomics & Biotechnology, Texas A&M University, College Station, TX, 77843, USA
| | - Göran Arnqvist
- Animal Ecology, Department of Ecology and Genetics, Uppsala University, Uppsala, 75236, Sweden
| | - Chaoliang Lei
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Keyan Zhu-Salzman
- Department of Entomology, Texas A&M University, College Station, TX, 77843, USA; Institute for Plant Genomics & Biotechnology, Texas A&M University, College Station, TX, 77843, USA.
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Bakovic V, Martin Cerezo ML, Höglund A, Fogelholm J, Henriksen R, Hargeby A, Wright D. The genomics of phenotypically differentiated Asellus aquaticus cave, surface stream and lake ecotypes. Mol Ecol 2021; 30:3530-3547. [PMID: 34002902 DOI: 10.1111/mec.15987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/30/2021] [Accepted: 05/04/2021] [Indexed: 12/15/2022]
Abstract
Organisms well suited for the study of ecotype formation have wide distribution ranges, where they adapt to multiple drastically different habitats repeatedly over space and time. Here we study such ecotypes in a Crustacean model, Asellus aquaticus, a commonly occurring isopod found in freshwater habitats as diverse as streams, caves and lakes. Previous studies focusing on cave vs. surface ecotypes have attributed depigmentation, eye loss and prolonged antennae to several south European cave systems. Likewise, surveys across multiple Swedish lakes have identified the presence of dark-pigmented "reed" and light-pigmented "stonewort" ecotypes, which can be found within the same lake. In this study, we sequenced the first draft genome of A. aquaticus, and subsequently use this to map reads and call variants in surface stream, cave and two lake ecotypes. In addition, the draft genome was combined with a RADseq approach to perform a quantitative trait locus (QTL) mapping study using a laboratory bred F2 and F4 cave × surface intercross. We identified genomic regions associated with body pigmentation, antennae length and body size. Furthermore, we compared genome-wide differentiation between natural populations and found several genes potentially associated with these habitats. The assessment of the cave QTL regions in the light-dark comparison of lake populations suggests that the regions associated with cave adaptation are also involved with genomic differentiation in the lake ecotypes. These demonstrate how troglomorphic adaptations can be used as a model for related ecotype formation.
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Affiliation(s)
- Vid Bakovic
- IFM Biology, University of Linköping, Linköping, Sweden
| | | | | | | | - Rie Henriksen
- IFM Biology, University of Linköping, Linköping, Sweden
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9
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Zhang QL, Li HW, Dong ZX, Yang XJ, Lin LB, Chen JY, Yuan ML. Comparative transcriptomic analysis of fireflies (Coleoptera: Lampyridae) to explore the molecular adaptations to fresh water. Mol Ecol 2020; 29:2676-2691. [PMID: 32512643 DOI: 10.1111/mec.15504] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 05/28/2020] [Accepted: 06/01/2020] [Indexed: 12/12/2022]
Abstract
Aquatic insects are well adapted to freshwater environments, but the molecular basis of these adaptations remains largely unknown. Most firefly species (Coleoptera: Lampyridae) are terrestrial, but the larvae of several species are aquatic. Here, larval and adult transcriptomes from Aquatica leii (freshwater) and Lychnuris praetexta (terrestrial) were generated to test whether the genes associated with metabolic efficiency and morphology have undergone adaptive evolution to fresh water. The aquatic fireflies had a significantly lower ratio of nonsynonymous to synonymous substitutions than the terrestrial insects, indicating a genomewide evolutionary constraint in the aquatic fireflies. We identified 341 fast-evolving genes and 116 positively selected genes in the aquatic fireflies. Of these, 76 genes exhibiting both fast evolution and positive selection were primarily involved in ATP production, energy metabolism and the hypoxia response. We identified 7,271 differentially expressed genes (DEGs) in A. leii (adults versus larvae) and 8,309 DEGs in L. praetexta (adults versus larvae). DEGs specific to the aquatic firefly (n = 1,445) were screened via interspecific comparisons (A. leii versus L. praetexta) and were significantly enriched for genes involved in metabolic efficiency (e.g., ATP production, hypoxia, and immune responses) and certain aspects of morphology (e.g., cuticle chitin, tracheal and compound eye morphology). These results indicate that sequence and expression-level changes in genes associated with both metabolic efficiency and morphological attributes related to the freshwater lifestyle contributed to freshwater adaptation in fireflies. This study provides new insights into the molecular mechanisms of aquatic adaptation in insects.
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Affiliation(s)
- Qi-Lin Zhang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Hong-Wei Li
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Zhi-Xiang Dong
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Xiao-Jie Yang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Lian-Bing Lin
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Jun-Yuan Chen
- LPS, Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, Nanjing, China
| | - Ming-Long Yuan
- State Key Laboratory of Grassland Agro-Ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University, Lanzhou, China
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10
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Mahneva O, Caplan SL, Ivko P, Dawson-Scully K, Milton SL. NO/cGMP/PKG activation protects Drosophila cells subjected to hypoxic stress. Comp Biochem Physiol C Toxicol Pharmacol 2019; 223:106-114. [PMID: 31150868 DOI: 10.1016/j.cbpc.2019.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 01/28/2023]
Abstract
The anoxia-tolerant fruit fly, Drosophila melanogaster, has routinely been used to examine cellular mechanisms responsible for anoxic and oxidative stress resistance. Nitric oxide (NO), an important cellular signaling molecule, and its downstream activation of cGMP-dependent protein kinase G (PKG) has been implicated as a protective mechanism against ischemic injury in diverse animal models from insects to mammals. In Drosophila, increased PKG signaling results in increased survival of animals exposed to anoxic stress. To determine if activation of the NO/cGMP/PKG pathway is protective at the cellular level, the present study employed a pharmacological protocol to mimic hypoxic injury in Drosophila S2 cells. The commonly used S2 cell line was derived from a primary culture of late stage (20-24 h old) Drosophila melanogaster embryos. Hypoxic stress was induced by exposure to either sodium azide (NaN3) or cobalt chloride (CoCl2). During chemical hypoxic stress, NO/cGMP/PKG activation protected against cell death and this mechanism involved modulation of downstream mitochondrial ATP-sensitive potassium ion channels (mitoKATP). The cellular protection afforded by NO/cGMP/PKG activation during ischemia-like stress may be an adaptive cytoprotective mechanism and modulation of this signaling cascade could serve as a potential therapeutic target for protection against hypoxia or ischemia-induced cellular injury.
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Affiliation(s)
- Olena Mahneva
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
| | - Stacee Lee Caplan
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
| | - Polina Ivko
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
| | - Sarah L Milton
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
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11
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A Cell Density-Dependent Reporter in the Drosophila S2 Cells. Sci Rep 2019; 9:11868. [PMID: 31413273 PMCID: PMC6694118 DOI: 10.1038/s41598-019-47652-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 07/22/2019] [Indexed: 01/20/2023] Open
Abstract
Cell density regulates many aspects of cell properties and behaviors including metabolism, growth, cytoskeletal structure and locomotion. Importantly, the responses by cultured cells to density signals also uncover key mechanisms that govern animal development and diseases in vivo. Here we characterized a density-responsive reporter system in transgenic Drosophila S2 cells. We show that the reporter genes are strongly induced in a cell density-dependent and reporter-independent fashion. The rapid and reversible induction occurs at the level of mRNA accumulation. We show that multiple DNA elements within the transgene sequences, including a metal response element from the metallothionein gene, contribute to the reporter induction. The reporter induction correlates with changes in multiple cell density and growth regulatory pathways including hypoxia, apoptosis, cell cycle and cytoskeletal organization. Potential applications of such a density-responsive reporter will be discussed.
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12
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TORC1 modulation in adipose tissue is required for organismal adaptation to hypoxia in Drosophila. Nat Commun 2019; 10:1878. [PMID: 31015407 PMCID: PMC6478872 DOI: 10.1038/s41467-019-09643-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 03/19/2019] [Indexed: 12/27/2022] Open
Abstract
Animals often develop in environments where conditions such as food, oxygen and temperature fluctuate. The ability to adapt their metabolism to these fluctuations is important for normal development and viability. In most animals, low oxygen (hypoxia) is deleterious. However some animals can alter their physiology to tolerate hypoxia. Here we show that TORC1 modulation in adipose tissue is required for organismal adaptation to hypoxia in Drosophila. We find that hypoxia rapidly suppresses TORC1 signaling in Drosophila larvae via TSC-mediated inhibition of Rheb. We show that this hypoxia-mediated inhibition of TORC1 specifically in the larval fat body is essential for viability. Moreover, we find that these effects of TORC1 inhibition on hypoxia tolerance are mediated through remodeling of fat body lipid storage. These studies identify the larval adipose tissue as a key hypoxia-sensing tissue that coordinates whole-body development and survival to changes in environmental oxygen by modulating TORC1 and lipid metabolism.
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Ding D, Liu G, Hou L, Gui W, Chen B, Kang L. Genetic variation in PTPN1 contributes to metabolic adaptation to high-altitude hypoxia in Tibetan migratory locusts. Nat Commun 2018; 9:4991. [PMID: 30478313 PMCID: PMC6255802 DOI: 10.1038/s41467-018-07529-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 11/01/2018] [Indexed: 12/21/2022] Open
Abstract
Animal and human highlanders have evolved distinct traits to enhance tissue oxygen delivery and utilization. Unlike vertebrates, insects use their tracheal system for efficient oxygen delivery. However, the genetic basis of insect adaptation to high-altitude hypoxia remains unexplored. Here, we report a potential mechanism of metabolic adaptation of migratory locusts in the Tibetan Plateau, through whole-genome resequencing and functional investigation. A genome-wide scan revealed that the positively selected genes in Tibetan locusts are predominantly involved in carbon and energy metabolism. We observed a notable signal of natural selection in the gene PTPN1, which encodes PTP1B, an inhibitor of insulin signaling pathway. We show that a PTPN1 coding mutation regulates the metabolism of Tibetan locusts by mediating insulin signaling activity in response to hypoxia. Overall, our findings provide evidence for the high-altitude hypoxia adaptation of insects at the genomic level and explore a potential regulatory mechanism underlying the evolved metabolic homeostasis. Vertebrate adaptation to high-altitude life has been extensively investigated, while invertebrates are less well-studied. Here, the authors find signals of adaptive evolution in genomes of migratory locusts from the Tibetan Plateau, and implicate a PTPN1 coding mutation in their hypoxia response.
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Affiliation(s)
- Ding Ding
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guangjian Liu
- Novogene Bioinformatics Institute, 100083, Beijing, China
| | - Li Hou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China
| | - Wanying Gui
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bing Chen
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China.
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China.
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14
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Wang L, Cui S, Liu Z, Ping Y, Qiu J, Geng X. Inhibition of mitochondrial respiration under hypoxia and increased antioxidant activity after reoxygenation of Tribolium castaneum. PLoS One 2018; 13:e0199056. [PMID: 29902250 PMCID: PMC6002095 DOI: 10.1371/journal.pone.0199056] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 05/30/2018] [Indexed: 12/25/2022] Open
Abstract
Regulating the air in low-oxygen environments protects hermetically stored grains from storage pests damage. However, pests that can tolerate hypoxic stress pose a huge challenge in terms of grain storage. We used various biological approaches to determine the fundamental mechanisms of Tribolium castaneum to cope with hypoxia. Our results indicated that limiting the available oxygen to T. castaneum increased glycolysis and inhibited the Krebs cycle, and that accumulated pyruvic acid was preferentially converted to lactic acid via anaerobic metabolism. Mitochondrial aerobic respiration was markedly suppressed for beetles under hypoxia, which also might have led to mitochondrial autophagy. The enzymatic activity of citrate synthase decreased in insects under hypoxia but recovered within 12 h, which suggested that the beetles recovered from the hypoxia. Moreover, hypoxia-reperfusion resulted in severe oxidative damage to insects, and antioxidant levels increased to defend against the high level of reactive oxygen species. In conclusion, our findings show that mitochondria were the main target in T. castaneum in response to low oxygen. The beetles under hypoxia inhibited mitochondrial respiration and increased antioxidant activity after reoxygenation. Our research advances the field of pest control and makes it possible to develop more efficient strategies for hermetic storage.
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Affiliation(s)
- Lei Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, PR China
| | - Sufen Cui
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, PR China
| | - Zhicheng Liu
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, PR China
| | - Yong Ping
- Bio-X institutes, Shanghai Jiao Tong University, Shanghai, PR China
| | - Jiangping Qiu
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, PR China
| | - Xueqing Geng
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, PR China
- * E-mail:
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15
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de Toeuf B, Soin R, Nazih A, Dragojevic M, Jurėnas D, Delacourt N, Vo Ngoc L, Garcia-Pino A, Kruys V, Gueydan C. ARE-mediated decay controls gene expression and cellular metabolism upon oxygen variations. Sci Rep 2018; 8:5211. [PMID: 29581565 PMCID: PMC5980108 DOI: 10.1038/s41598-018-23551-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 03/14/2018] [Indexed: 12/18/2022] Open
Abstract
Hypoxia triggers profound modifications of cellular transcriptional programs. Upon reoxygenation, cells return to a normoxic gene expression pattern and mRNA produced during the hypoxic phase are degraded. TIS11 proteins control deadenylation and decay of transcripts containing AU-rich elements (AREs). We observed that the level of dTIS11 is decreased in hypoxic S2 Drosophila cells and returns to normal level upon reoxygenation. Bioinformatic analyses using the ARE-assessing algorithm AREScore show that the hypoxic S2 transcriptome is enriched in ARE-containing transcripts and that this trend is conserved in human myeloid cells. Moreover, an efficient down-regulation of Drosophila ARE-containing transcripts during hypoxia/normoxia transition requires dtis11 expression. Several of these genes encode proteins with metabolic functions. Here, we show that ImpL3 coding for Lactate Dehydrogenase in Drosophila, is regulated by ARE-mediated decay (AMD) with dTIS11 contributing to ImpL3 rapid down-regulation upon return to normal oxygen levels after hypoxia. More generally, we observed that dtis11 expression contributes to cell metabolic and proliferative recovery upon reoxygenation. Altogether, our data demonstrate that AMD plays an important role in the control of gene expression upon variation in oxygen concentration and contributes to optimal metabolic adaptation to oxygen variations.
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Affiliation(s)
- Bérengère de Toeuf
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université libre de Bruxelles (ULB), 12 rue des Profs. Jeener et Brachet, 6041, Gosselies, Belgium
| | - Romuald Soin
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université libre de Bruxelles (ULB), 12 rue des Profs. Jeener et Brachet, 6041, Gosselies, Belgium
| | - Abdelkarim Nazih
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université libre de Bruxelles (ULB), 12 rue des Profs. Jeener et Brachet, 6041, Gosselies, Belgium
| | - Marija Dragojevic
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université libre de Bruxelles (ULB), 12 rue des Profs. Jeener et Brachet, 6041, Gosselies, Belgium
| | - Dukas Jurėnas
- Laboratoire de Microbiologie Moléculaire et Cellulaire, Faculté des Sciences, Université libre de Bruxelles (ULB), 12 rue des Profs. Jeener et Brachet, 6041, Gosselies, Belgium
| | - Nadège Delacourt
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université libre de Bruxelles (ULB), 12 rue des Profs. Jeener et Brachet, 6041, Gosselies, Belgium
| | - Long Vo Ngoc
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université libre de Bruxelles (ULB), 12 rue des Profs. Jeener et Brachet, 6041, Gosselies, Belgium
- Section of Molecular Biology, University of California at San Diego, La Jolla, California, 92093, USA
| | - Abel Garcia-Pino
- Laboratoire de Microbiologie Moléculaire et Cellulaire, Faculté des Sciences, Université libre de Bruxelles (ULB), 12 rue des Profs. Jeener et Brachet, 6041, Gosselies, Belgium
| | - Véronique Kruys
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université libre de Bruxelles (ULB), 12 rue des Profs. Jeener et Brachet, 6041, Gosselies, Belgium
| | - Cyril Gueydan
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université libre de Bruxelles (ULB), 12 rue des Profs. Jeener et Brachet, 6041, Gosselies, Belgium.
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16
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Hall H, Medina P, Cooper DA, Escobedo SE, Rounds J, Brennan KJ, Vincent C, Miura P, Doerge R, Weake VM. Transcriptome profiling of aging Drosophila photoreceptors reveals gene expression trends that correlate with visual senescence. BMC Genomics 2017; 18:894. [PMID: 29162050 PMCID: PMC5698953 DOI: 10.1186/s12864-017-4304-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 11/14/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Aging is associated with functional decline of neurons and increased incidence of both neurodegenerative and ocular disease. Photoreceptor neurons in Drosophila melanogaster provide a powerful model for studying the molecular changes involved in functional senescence of neurons since decreased visual behavior precedes retinal degeneration. Here, we sought to identify gene expression changes and the genomic features of differentially regulated genes in photoreceptors that contribute to visual senescence. RESULTS To identify gene expression changes that could lead to visual senescence, we characterized the aging transcriptome of Drosophila sensory neurons highly enriched for photoreceptors. We profiled the nuclear transcriptome of genetically-labeled photoreceptors over a 40 day time course and identified increased expression of genes involved in stress and DNA damage response, and decreased expression of genes required for neuronal function. We further show that combinations of promoter motifs robustly identify age-regulated genes, suggesting that transcription factors are important in driving expression changes in aging photoreceptors. However, long, highly expressed and heavily spliced genes are also more likely to be downregulated with age, indicating that other mechanisms could contribute to expression changes at these genes. Lastly, we identify that circular RNAs (circRNAs) strongly increase during aging in photoreceptors. CONCLUSIONS Overall, we identified changes in gene expression in aging Drosophila photoreceptors that could account for visual senescence. Further, we show that genomic features predict these age-related changes, suggesting potential mechanisms that could be targeted to slow the rate of age-associated visual decline.
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Affiliation(s)
- Hana Hall
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Patrick Medina
- Department of Statistics, Purdue University, West Lafayette, IN, 47907, USA
| | - Daphne A Cooper
- Department of Biology, University of Nevada, Reno, NV, 89557, USA
| | - Spencer E Escobedo
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Jeremiah Rounds
- Department of Statistics, Purdue University, West Lafayette, IN, 47907, USA
| | - Kaelan J Brennan
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | | | - Pedro Miura
- Department of Biology, University of Nevada, Reno, NV, 89557, USA
| | | | - Vikki M Weake
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA. .,Purdue University Center for Cancer Research, Purdue University, West Lafayette, 47907, USA.
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17
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Teets NM, Denlinger DL. Quantitative Phosphoproteomics Reveals Signaling Mechanisms Associated with Rapid Cold Hardening in a Chill-Tolerant Fly. J Proteome Res 2016; 15:2855-62. [DOI: 10.1021/acs.jproteome.6b00427] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Nicholas M. Teets
- Department of Entomology and ‡Department of Evolution, Ecology, and Organismal
Biology, Ohio State University, Columbus, Ohio 43210, United States
| | - David L. Denlinger
- Department of Entomology and ‡Department of Evolution, Ecology, and Organismal
Biology, Ohio State University, Columbus, Ohio 43210, United States
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18
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Wang L, Cui S, Ma L, Kong L, Geng X. Current advances in the novel functions of hypoxia-inducible factor and prolyl hydroxylase in invertebrates. INSECT MOLECULAR BIOLOGY 2015; 24:634-648. [PMID: 26387499 DOI: 10.1111/imb.12189] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Oxygen is essential for aerobic life, and hypoxia has very severe consequences. Organisms need to overcome low oxygen levels to maintain biological functions during normal development and in disease states. The mechanism underlying the hypoxic response has been widely investigated in model animals such as Drosophila melanogaster and Caenorhabditis elegans. Hypoxia-inducible factor (HIF), a key gene product in the response to oxygen deprivation, is primarily regulated by prolyl hydroxylase domain enzymes (PHDs). However, recent findings have uncovered novel HIF-independent functions of PHDs. This review provides an overview of how invertebrates are able to sustain hypoxic damages, and highlights some recent discoveries in the regulation of cellular signalling by PHDs. Given that some core genes and major pathways are evolutionarily conserved, these research findings could provide insight into oxygen-sensitive signalling in mammals, and have biomedical implications for human diseases.
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Affiliation(s)
- L Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, Shanghai, China
| | - S Cui
- School of Agriculture and Biology, Shanghai Jiao Tong University, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, Shanghai, China
| | - L Ma
- School of Agriculture and Biology, Shanghai Jiao Tong University, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, Shanghai, China
| | - L Kong
- School of Agriculture and Biology, Shanghai Jiao Tong University, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, Shanghai, China
| | - X Geng
- School of Agriculture and Biology, Shanghai Jiao Tong University, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, Shanghai, China
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19
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DeLalio LJ, Dion SM, Bootes AM, Smith WA. Direct effects of hypoxia and nitric oxide on ecdysone secretion by insect prothoracic glands. JOURNAL OF INSECT PHYSIOLOGY 2015; 76:56-66. [PMID: 25747870 DOI: 10.1016/j.jinsphys.2015.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 02/19/2015] [Accepted: 02/22/2015] [Indexed: 06/04/2023]
Abstract
Insect molting and metamorphosis are controlled by the molt stimulating hormone ecdysone. A recent study suggests that reduced tissue oxygenation correlates with the size-sensing mechanism responsible for triggering molting. When reared in hypoxia, larvae of Manduca sexta and Drosophila melanogaster initiate molting at lower weights than do larvae reared in normoxia. Furthermore, in Drosophila, the signaling gas nitric oxide (NO) appears to be required for normal developmental timing. As observed in Drosophila, NO signaling targets the nuclear hormone receptor beta fushi tarazu transcription factor 1 (βFTZ-F1) through activation of Drosophila hormone receptor 3 (DHR3), two key regulators of ecdysone production and metamorphic tissue progression. We set out to directly examine the effects of hypoxia and NO on ecdysone secretion using prothoracic glands from feeding fifth (last) larval stage M. sexta. Our results indicate that in vitro treatment of prothoracic glands with hypoxia (2% oxygen) or the NO donor DETA-NONOate significantly inhibit ecdysone secretion. Protein markers of glandular activity were also in keeping with an initial inhibition, measured a decrease in phosphorylated ERK (extracellular signal regulated kinase) and an increase in non-phosphorylated 4EBP (eukaryotic initiation factor 4E binding protein). Additionally, gene expression levels of Manduca hormone receptor 3 (mhr3), βftz-f1, nitric oxide synthase (nos), and the PTTH receptor torso, were quantified using real-time PCR. NO treatment increased mhr3 expression and decreased nos expression. Hypoxia increased mhr3 transcription after 2 hr, but decreased transcription after 12 hr, with no effect on nos expression. Both NO and hypoxia had small effects on βftz-f1 expression, yet strongly increased torso transcription. Our results demonstrate that, in isolated prothoracic glands, hypoxia and NO signaling directly inhibit ecdysteroid secretion, but at the same time alter aspects of prothoracic gland function that may enhance secretory response.
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Affiliation(s)
- Leon J DeLalio
- Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Avenue, Boston, MA 02115, USA
| | - Sara M Dion
- Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Avenue, Boston, MA 02115, USA
| | - Abigail M Bootes
- Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Avenue, Boston, MA 02115, USA
| | - Wendy A Smith
- Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Avenue, Boston, MA 02115, USA.
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20
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Annexin A2 promotes phagophore assembly by enhancing Atg16L⁺ vesicle biogenesis and homotypic fusion. Nat Commun 2015; 6:5856. [PMID: 25597631 PMCID: PMC4299943 DOI: 10.1038/ncomms6856] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 11/13/2014] [Indexed: 12/22/2022] Open
Abstract
Plasma membrane budding of Atg-16L-positive vesicles represents a very early event in the generation of the phagophore and in the process of macroautophagy. Here we show that the membrane curvature-inducing protein annexin A2 contributes to the formation of these vesicles and their fusion to form phagophores. Ultrastructural, proteomic and FACS analyses of Atg16L-positive vesicles reveal that 30% of Atg16L-positive vesicles are also annexin A2-positive. Lipidomic analysis of annexin A2-deficient mouse cells indicates that this protein plays a role in recruiting phosphatidylserine and phosphatidylinositides to Atg16L-positive vesicles. Absence of annexin A2 reduces both vesicle formation and homotypic Atg16L vesicle fusion. Ultimately, a reduction in LC3 flux and dampening of macroautophagy are observed in dendritic cells from Anxa2−/− mice. Together, our analyses highlight the importance of annexin A2 in vesiculation of a population of Atg16L-positive structures from the plasma membrane, and in their homotypic fusion to form phagophore structures. The earliest steps in autophagy are thought to include the budding of Atg16L-containing vesicles from the plasma membrane and their homotypic fusion to form a phagophore. Morozova et al. reveal a role for the membrane curvature-inducing protein Annexin A2 in the formation and fusion of these vesicles.
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21
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Otte KA, Fröhlich T, Arnold GJ, Laforsch C. Proteomic analysis of Daphnia magna hints at molecular pathways involved in defensive plastic responses. BMC Genomics 2014; 15:306. [PMID: 24762235 PMCID: PMC4236883 DOI: 10.1186/1471-2164-15-306] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 04/07/2014] [Indexed: 11/10/2022] Open
Abstract
Background Phenotypic plasticity in defensive traits occurs in many species when facing heterogeneous predator regimes. The waterflea Daphnia is well-known for showing a variety of these so called inducible defences. However, molecular mechanisms underlying this plasticity are poorly understood so far. We performed proteomic analysis on Daphnia magna exposed to chemical cues of the predator Triops cancriformis. D. magna develops an array of morphological changes in the presence of Triops including changes of carapace morphology and cuticle hardening. Results Using the 2D-DIGE technique, 1500 protein spots could be matched and quantified. We discovered 179 protein spots with altered intensity when comparing Triops exposed animals to a control group, and 69 spots were identified using nano-LC MS/MS. Kairomone exposure increased the intensity of spots containing muscle proteins, cuticle proteins and chitin-modifying enzymes as well as enzymes of carbohydrate and energy metabolism. The yolk precursor protein vitellogenin decreased in abundance in 41 of 43 spots. Conclusion Identified proteins may be either directly involved in carapace stability or reflect changes in energy demand and allocation costs in animals exposed to predator kairomones. Our results present promising candidate proteins involved in the expression of inducible defences in Daphnia and enable further in depth analysis of this phenomenon.
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22
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Zhou D, Haddad GG. Genetic analysis of hypoxia tolerance and susceptibility in Drosophila and humans. Annu Rev Genomics Hum Genet 2013; 14:25-43. [PMID: 23808366 DOI: 10.1146/annurev-genom-091212-153439] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Oxygen is essential for metazoans' life on earth. Oxygen deprivation, or hypoxia, contributes significantly to the pathophysiology of many human diseases. A better understanding of the fundamental molecular and genetic basis for adaptation to low-oxygen environments will help us develop therapeutic strategies to prevent or treat diseases that have hypoxia as a major part of their pathogenesis. Different cells and organisms have evolved different ways to cope with this life-threatening challenge, and the molecular and genetic mechanisms remain largely unknown. The current revolution of genomic technology has advanced our understanding of the genetic basis of many diseases and conditions, including hypoxia tolerance and susceptibility. In this review, we highlight the progress made in understanding the molecular responses to hypoxia in an animal model organism (Drosophila melanogaster) and genetic adaptation to high-altitude hypoxia in humans.
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Affiliation(s)
- Dan Zhou
- Department of Pediatrics (Division of Respiratory Medicine) and
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23
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Iranon NN, Miller DL. Interactions between oxygen homeostasis, food availability, and hydrogen sulfide signaling. Front Genet 2012; 3:257. [PMID: 23233860 PMCID: PMC3516179 DOI: 10.3389/fgene.2012.00257] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 11/04/2012] [Indexed: 12/19/2022] Open
Abstract
The ability to sense and respond to stressful conditions is essential to maintain organismal homeostasis. It has long been recognized that stress response factors that improve survival in changing conditions can also influence longevity. In this review, we discuss different strategies used by animals in response to decreased O(2) (hypoxia) to maintain O(2) homeostasis, and consider interactions between hypoxia responses, nutritional status, and H(2)S signaling. O(2) is an essential environmental nutrient for almost all metazoans as it plays a fundamental role in development and cellular metabolism. However, the physiological response(s) to hypoxia depend greatly on the amount of O(2) available. Animals must sense declining O(2) availability to coordinate fundamental metabolic and signaling pathways. It is not surprising that factors involved in the response to hypoxia are also involved in responding to other key environmental signals, particularly food availability. Recent studies in mammals have also shown that the small gaseous signaling molecule hydrogen sulfide (H(2)S) protects against cellular damage and death in hypoxia. These results suggest that H(2)S signaling also integrates with hypoxia response(s). Many of the signaling pathways that mediate the effects of hypoxia, food deprivation, and H(2)S signaling have also been implicated in the control of lifespan. Understanding how these pathways are coordinated therefore has the potential to reveal new cellular and organismal homeostatic mechanisms that contribute to longevity assurance in animals.
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Affiliation(s)
- Nicole N Iranon
- Department of Biochemistry, University of Washington School of Medicine Seattle, WA, USA ; Molecular and Cellular Biology Graduate Program, University of Washington School of Medicine Seattle, WA, USA
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Katewa SD, Kapahi P. Role of TOR signaling in aging and related biological processes in Drosophila melanogaster. Exp Gerontol 2011; 46:382-90. [PMID: 21130151 PMCID: PMC3058120 DOI: 10.1016/j.exger.2010.11.036] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Revised: 11/23/2010] [Accepted: 11/23/2010] [Indexed: 01/22/2023]
Abstract
Extensive studies in model organisms in the last few decades have revealed that aging is subject to profound genetic influence. The conserved nutrient sensing TOR (Target of Rapamycin) pathway is emerging as a key regulator of lifespan and healthspan in various species from yeast to mammals. The TOR signaling pathway plays a critical role in determining how a eukaryotic cell or a cellular system co-ordinates its growth, development and aging in response to constant changes in its surrounding environment? TOR integrates signals originating from changes in growth factors, nutrient availability, energy status and various physiological stresses. Each of these inputs is specialized to sense particular signal(s), and conveys it to the TOR complex which in turn relays the signal to downstream outputs to appropriately respond to the environmental changes. These outputs include mRNA translation, autophagy, transcription, metabolism, cell survival, proliferation and growth amongst a number of other cellular processes, some of which influence organismal lifespan. Here we review the contribution of the model organism Drosophila in the understanding of TOR signaling and the various biological processes it modulates that may impact on aging. Drosophila was the first organism where the nutrient dependent effects of the TOR pathway on lifespan were first uncovered. We also discuss how the nutrient-sensing TOR pathway appears to be critically important for mediating the longevity effects of dietary restriction (DR), a potent environmental method of lifespan extension by nutrient limitation. Identifying the molecular mechanisms that modulate lifespan downstream of TOR is being intensely investigated and there is hope that these are likely to serve as potential targets for amelioration of age-related diseases and enhance healthful lifespan extension in humans.
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25
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McCormick MA, Tsai SY, Kennedy BK. TOR and ageing: a complex pathway for a complex process. Philos Trans R Soc Lond B Biol Sci 2011; 366:17-27. [PMID: 21115526 DOI: 10.1098/rstb.2010.0198] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Studies in invertebrate model organisms have led to a wealth of knowledge concerning the ageing process. But which of these discoveries will apply to ageing in humans? Recently, an assessment of the degree of conservation of ageing pathways between two of the leading invertebrate model organisms, Saccharomyces cerevisiae and Caenorhabditis elegans, was completed. The results (i) quantitatively indicated that pathways were conserved between evolutionarily disparate invertebrate species and (ii) emphasized the importance of the TOR kinase pathway in ageing. With recent findings that deletion of the mTOR substrate S6K1 or exposure of mice to the mTOR inhibitor rapamycin result in lifespan extension, mTOR signalling has become a major focus of ageing research. Here, we address downstream targets of mTOR signalling and their possible links to ageing. We also briefly cover other ageing genes identified by comparing worms and yeast, addressing the likelihood that their mammalian counterparts will affect longevity.
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Affiliation(s)
- Mark A McCormick
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
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26
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Cell-type-dependent regulation of mTORC1 by REDD1 and the tumor suppressors TSC1/TSC2 and LKB1 in response to hypoxia. Mol Cell Biol 2011; 31:1870-84. [PMID: 21383064 DOI: 10.1128/mcb.01393-10] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
mTORC1 is a critical regulator of cell growth that integrates multiple signals and is deregulated in cancer. We previously reported that mTORC1 regulation by hypoxia involves Redd1 and the Tsc1/Tsc2 complex. Here we show that Redd1 induction by hypoxia is tissue dependent and that hypoxia signals are relayed to mTORC1 through different pathways in a tissue-specific manner. In the liver, Redd1 induction is restricted to the centrilobular area, and in primary hepatocytes, mTORC1 inhibition by hypoxia is independent of Redd1. Furthermore, Tsc1/Tsc2 and Arnt (Hif-1β) are similarly dispensable. Hypoxia signaling in hepatocytes involves Lkb1, AMP-activated protein kinase (AMPK), and raptor. Differences in signal relay extend beyond hypoxia and involve AMPK signaling. AMPK activation (using 5-aminoimidazole-4-carboxamide riboside [AICAR]) induces raptor phosphorylation and inhibits mTORC1 in both mouse embryo fibroblasts (MEFs) and hepatocytes, but whereas mTORC1 inhibition is Tsc1/Tsc2 dependent in MEFs, it is independent in hepatocytes. In liver cells, raptor phosphorylation is essential for both AMPK and hypoxia signaling. Thus, context-specific signals are required for raptor phosphorylation-induced mTORC1 inhibition. Our data illustrate a heretofore unappreciated topological complexity in mTORC1 regulation. Interestingly, topological differences in mTORC1 regulation by the tumor suppressor proteins Lkb1 and Tsc1/Tsc2 may underlie their tissue specificity of tumor suppressor action.
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Azevedo SV, Caranton OAM, de Oliveira TL, Hartfelder K. Differential expression of hypoxia pathway genes in honey bee (Apis mellifera L.) caste development. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:38-45. [PMID: 20887729 DOI: 10.1016/j.jinsphys.2010.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 09/21/2010] [Accepted: 09/22/2010] [Indexed: 05/29/2023]
Abstract
Diphenism in social bees is essentially contingent on nutrient-induced cellular and systemic physiological responses resulting in divergent gene expression patterns. Analyses of juvenile hormone (JH) titers and functional genomics assays of the insulin-insulin-like signaling (IIS) pathway and its associated branch, target-of-rapamycin (TOR), revealed systemic responses underlying honey bee (Apis mellifera) caste development. Nevertheless, little attention has been paid to cellular metabolic responses. Following up earlier investigations showing major caste differences in oxidative metabolism and mitochondrial physiology, we herein identified honey bee homologs of hypoxia signaling factors, HIFα/Sima, HIFβ/Tango and PHD/Fatiga and we investigated their transcript levels throughout critical stages of larval development. Amsima, Amtango and Amfatiga showed correlated transcriptional activity, with two peaks of occurring in both queens and workers, the first one shortly after the last larval molt and the second during the cocoon-spinning phase. Transcript levels for the three genes were consistently higher in workers. As there is no evidence for major microenvironmental differences in oxygen levels within the brood nest area, this appears to be an inherent caste character. Quantitative PCR analyses on worker brain, ovary, and leg imaginal discs showed that these tissues differ in transcript levels. Being a highly conserved pathway and linked to IIS/TOR, the hypoxia gene expression pattern seen in honey bee larvae denotes that the hypoxia pathway has undergone a transformation, at least during larval development, from a response to environmental oxygen concentrations to an endogenous regulatory factor in the diphenic development of honey bee larvae.
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Affiliation(s)
- Sergio Vicente Azevedo
- Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, Brazil.
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Abstract
RNA interference (RNAi) is an effective tool for genome-scale, high-throughput analysis of gene function. In the past five years, a number of genome-scale RNAi high-throughput screens (HTSs) have been done in both Drosophila and mammalian cultured cells to study diverse biological processes, including signal transduction, cancer biology, and host cell responses to infection. Results from these screens have led to the identification of new components of these processes and, importantly, have also provided insights into the complexity of biological systems, forcing new and innovative approaches to understanding functional networks in cells. Here, we review the main findings that have emerged from RNAi HTS and discuss technical issues that remain to be improved, in particular the verification of RNAi results and validation of their biological relevance. Furthermore, we discuss the importance of multiplexed and integrated experimental data analysis pipelines to RNAi HTS.
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Affiliation(s)
- Stephanie Mohr
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115
- Drosophila RNAi Screening Center, Harvard Medical School, Boston, Massachusetts 02115
| | - Chris Bakal
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115
- Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115
- Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115
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Abstract
The insulin signalling pathway is highly conserved from mammals to Drosophila. Insulin signalling in the fly, as in mammals, regulates a number of physiological functions, including carbohydrate and lipid metabolism, tissue growth and longevity. In the present review, I discuss the molecular mechanisms by which insulin signalling regulates metabolism in Drosophila, comparing and contrasting with the mammalian system. I discuss both the intracellular signalling network, as well as the communication between organs in the fly.
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Dijkers PF, O'Farrell PH. Dissection of a hypoxia-induced, nitric oxide-mediated signaling cascade. Mol Biol Cell 2009; 20:4083-90. [PMID: 19625446 DOI: 10.1091/mbc.e09-05-0362] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Befitting oxygen's key role in life's processes, hypoxia engages multiple signaling systems that evoke pervasive adaptations. Using surrogate genetics in a powerful biological model, we dissect a poorly understood hypoxia-sensing and signal transduction system. Hypoxia triggers NO-dependent accumulation of cyclic GMP and translocation of cytoplasmic GFP-Relish (an NFkappaB/Rel transcription factor) to the nucleus in Drosophila S2 cells. An enzyme capable of eliminating NO interrupted signaling specifically when it was targeted to the mitochondria, arguing for a mitochondrial NO signal. Long pretreatment with an inhibitor of nitric oxide synthase (NOS), L-NAME, blocked signaling. However, addition shortly before hypoxia was without effect, suggesting that signaling is supported by the prior action of NOS and is independent of NOS action during hypoxia. We implicated the glutathione adduct, GSNO, as a signaling mediator by showing that overexpression of the cytoplasmic enzyme catalyzing its destruction, GSNOR, blocks signaling, whereas knockdown of this activity caused reporter translocation in the absence of hypoxia. In downstream steps, cGMP accumulated, and calcium-dependent signaling was subsequently activated via cGMP-dependent channels. These findings reveal the use of unconventional steps in an NO pathway involved in sensing hypoxia and initiating signaling.
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Affiliation(s)
- Pascale F Dijkers
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143-2200, USA
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Insulin/TOR signaling in growth and homeostasis: a view from the fly world. Int J Biochem Cell Biol 2008; 41:1006-10. [PMID: 18992839 DOI: 10.1016/j.biocel.2008.10.010] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 10/07/2008] [Accepted: 10/14/2008] [Indexed: 01/04/2023]
Abstract
The insulin/TOR pathway is a conserved regulator of cell and organism growth in metazoans. Over the last several years, an array of signaling inputs to this pathway has been defined. However the growth-regulatory outputs are less clear. Drosophila has proven to be a powerful genetic model system in which to study insulin/TOR signaling. This review highlights recent studies in Drosophila that have identified essential outputs and key effectors of the pathway. These include the regulation of ribosome synthesis, mRNA translation, autophagy and endocytosis, through downstream effectors such as Myc, FOXO, HIF1-alpha, TIF-IA, 4EBP and Atg1. This network of outputs and effectors can regulate cell and organismal metabolism, and is essential for the control of tissue growth, responses to starvation and stress, and aging. The mechanisms identified in Drosophila likely operate in most metazoans, and are relevent to our understanding of diseases caused by aberrent insulin/TOR signaling such as cancer, diabetes and obesity.
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