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You S, Yao S, Chen X, Hou Q, Liu Z, Lei G, Xie X, Liang Z, Yuchi Z, You M, Liu Y, Xiong L. CRISPR/Cas9-Mediated Knockout of the PxJHBP Gene Resulted in Increased Susceptibility to Bt Cry1Ac Protoxin and Reduced Lifespan and Spawning Rates in Plutella xylostella. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:8180-8188. [PMID: 38556749 DOI: 10.1021/acs.jafc.3c08721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
Juvenile hormone binding protein (JHBP) is a key regulator of JH signaling, and crosstalk between JH and 20-hydroxyecdysone (20E) can activate and fine-tune the mitogen-activated protein kinase cascade, leading to resistance to insecticidal proteins from Bacillis thuringiensis (Bt). However, the involvement of JHBP in the Bt Cry1Ac resistance of Plutella xylostella remains unclear. Here, we cloned a full-length cDNA encoding JHBP, and quantitative real-time PCR (qPCR) analysis showed that the expression of the PxJHBP gene in the midgut of the Cry1Ac-susceptible strain was significantly higher than that of the Cry1Ac-resistant strain. Furthermore, CRISPR/Cas9-mediated knockout of the PxJHBP gene significantly increased Cry1Ac susceptibility, resulting in a significantly shorter lifespan and reduced fertility. These results demonstrate that PxJHBP plays a critical role in the resistance to Cry1Ac protoxin and in the regulation of physiological metabolic processes associated with reproduction in adult females, providing valuable insights to improve management strategies of P. xylostella.
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Affiliation(s)
- Shijun You
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Life Science, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou 350002, China
| | - Shuyuan Yao
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Life Science, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou 350002, China
| | - Xuanhao Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Life Science, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou 350002, China
| | - Qing Hou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Life Science, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou 350002, China
| | - Zhaoxia Liu
- College of Oceanology and Food Science, Quanzhou Normal University, Quanzhou 362000, China
| | - Gaoke Lei
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Life Science, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou 350002, China
| | | | | | - Zhiguang Yuchi
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, China
| | - Minsheng You
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Life Science, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou 350002, China
| | - Yuanyuan Liu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Life Science, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lei Xiong
- Institute of Plant Protection, Jiangxi Academy of Agricultural Sciences, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops and College of Life Science, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Nanchang 3302002, China
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Zhang W, Liang G, Ma L, Jiang T, Xiao H. Dissecting the Role of Juvenile Hormone Binding Protein in Response to Hormone and Starvation in the Cotton Bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2019; 112:1411-1417. [PMID: 30789202 DOI: 10.1093/jee/toz027] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/17/2019] [Accepted: 01/30/2019] [Indexed: 06/09/2023]
Abstract
Juvenile hormone (JH) regulates many physiological processes in insect development, diapause, and reproduction. Juvenile hormone binding protein (JHBP), the carrier partner protein of JH, is essential for the balance of JH titer to regulate the metamorphosis and development of insect. In this study, two JHBP genes were identified from Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), namely HaJHBP1 and HaJHBP2. The tissue and temporal expression pattern revealed that both HaJHBP1 and HaJHBP2 were dominantly expressed in larval fat body, and their high transcription stages were detected in fourth and fifth instars. The ingestion of methoprene, a JH analogue, significantly induced the expression of HaJHBP1 and HaJHBP2. However, both HaJHBP1 and HaJHBP2 mRNA levels were significantly downregulated after treated with a JH antagonist, precocene. When subject to starvation, larvae showed a marked suppressive effect in the expression of HaJHBP1 and HaJHBP2. These results indicate that JHBP plays a part in the JH-regulated metabolism, growth, or development in reaction to different nutritional conditions.
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Affiliation(s)
- Wanna Zhang
- Institute of Entomology, Jiangxi Agricultural University, Nanchang, China
| | - Gemei Liang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Long Ma
- College of Life Sciences, Jiangxi Science & Technology Normal University, Nanchang, China
| | - Ting Jiang
- Institute of Entomology, Jiangxi Agricultural University, Nanchang, China
| | - Haijun Xiao
- Institute of Entomology, Jiangxi Agricultural University, Nanchang, China
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Li W, Cheng T, Hu W, Peng Z, Liu C, Xia Q. Genome-wide identification and analysis of JHBP-domain family members in the silkworm Bombyx mori. Mol Genet Genomics 2016; 291:2159-2171. [PMID: 27631967 DOI: 10.1007/s00438-016-1245-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/29/2016] [Indexed: 12/20/2022]
Abstract
Juvenile hormone (JH) regulates the insect growth and development. JH appears in the hemolymph bound by a specific glycoprotein, juvenile hormone-binding protein (JHBP), which serves as a carrier to release the hormone to target tissues and cells. However, JHBP family candidates, expression patterns, and functional implications are still unclear. In this study, we identified 41 genes-containing conserved JHBP domains distributed across eight chromosomes of the silkworm Bombyx mori. A phylogenetic tree showed that the silkworm JHBP (BmJHBP) genes could be classified into two major branches and four subfamilies. Microarray data revealed that BmJHBP genes exhibit various expression patterns and are expressed in different tissues, periods, and sexes. The expression of BmJHBP genes was generally higher in the head, integument, midgut, fat body, testis, and ovary than in the anterior of the silk gland (ASG), median of the silk gland (MSG), posterior of the silk gland (PSG), hemocyte, and Malpighian tubule. BmJHBPd2, in particular, was investigated by Western Blotting, and immunofluorescent assay and was found to be highly expressed in the PSG cytoplasm on day 3 of the fifth instar, coinciding with silk production. Taken together, our findings will be useful in improving understanding the complexity of the JHBP family, and will lay the foundation of explaining functional characterization for further research.
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Affiliation(s)
- Wei Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Tingcai Cheng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Wenbo Hu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Zhangchuan Peng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Chun Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China. .,Chongqing Engineering and Technology Research Center for Novel Silk Materials, Chongqing, 400716, China.
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China.,Chongqing Engineering and Technology Research Center for Novel Silk Materials, Chongqing, 400716, China
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Proteome analysis of male accessory gland secretions in oriental fruit flies reveals juvenile hormone-binding protein, suggesting impact on female reproduction. Sci Rep 2015; 5:16845. [PMID: 26582577 PMCID: PMC4652233 DOI: 10.1038/srep16845] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 10/21/2015] [Indexed: 01/14/2023] Open
Abstract
In insects, the accessory gland proteins (Acps) secreted by male accessory glands (MAGs) account for the majority of seminal fluids proteins. Mixed with sperm, they are transferred to the female at mating and so impact reproduction. In this project, we identified 2,927 proteins in the MAG secretions of the oriental fruit fly Bactrocera dorsalis, an important agricultural pest worldwide, using LC-MS analysis, and all sequences containing open reading frames were analyzed using signalP. In total, 90 Acps were identified. About one third (26) of these 90 Acps had a specific functional description, while the other two thirds (64) had no functional description including dozens of new classes of proteins. Hence, several of these novel Acps were abundant in the MAG secretions, and we confirmed their MAG-specific expression by qPCR. Finally and interestingly, one of these novel proteins was functionally predicted as juvenile hormone-binding protein, suggesting the impact of Acps with reproductive events in the female. Our results will aid in the development of an experimental method to identify Acps in insects, and in turn this information with new Acps in B. dorsalis will pave the way of further exploration their function in reproduction and potential development as new insecticide targets.
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Ritdachyeng E, Manaboon M, Tobe SS, Singtripop T. Molecular characterization and gene expression of juvenile hormone binding protein in the bamboo borer, Omphisa fuscidentalis. JOURNAL OF INSECT PHYSIOLOGY 2012; 58:1493-1501. [PMID: 23000738 DOI: 10.1016/j.jinsphys.2012.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 09/04/2012] [Accepted: 09/05/2012] [Indexed: 06/01/2023]
Abstract
Juvenile hormone (JH) plays an important role in many physiological processes in insect development, diapause and reproduction. An appropriate JH titer in hemolymph is essential for normal development in insects. Information concerning its carrier partner protein, juvenile hormone binding protein (JHBP), provides an alternative approach to understanding how JH regulates metamorphosis. In this study, we cloned and sequenced the Omphisa juvenile hormone binding protein (OfJHBP). The full-length OfJHBP cDNA sequence is comprised of 849 nucleotides with an open reading frame of 726bp encoding 242 amino acids. The molecular mass of the protein was estimated to be 26.94kDa. The deduced protein sequence of OfJHBP showed moderate homology with the lepidopteran, Heliothis virescens JHBP (52% amino acid identity) and lower homology with the Bombyx mori JHBP (45%) and the Manduca sexta JHBP (44%). The OfJHBP was expressed mainly in the fat body. OfJHBP transcripts in the fat body was moderately high during 3rd, 4th and 5th instars, then rapidly increased, reaching a peak during early diapause. The expression remained high in mid-diapause, then decreased in late-diapause until the pupal stage. Both juvenile hormone analog (JHA), methoprene, 20-hydroxyecdysone (20E) exhibited a similar stimulatory pattern in OfJHBP expression of diapausing larvae. OfJHBP mRNA levels gradually increased and showed a peak of gene expression on the penultimate, then declined to low levels in the pupal stage. For in vitro gene expression, both of JHA and 20E induced OfJHBP mRNA expression in fat body. Fat body maintenance in vitro in the presence of 0.1μg/50μl JHA induced OfJHBP mRNA expression to high levels within the first 30min whereas 0.1μg/50μl 20E induced gene expression at 120min. To study the synergistic effect of these two hormones, fat body was incubated in vitro with 0.1μg/50μl JHA or 0.1μg/50μl 20E or a combination of both hormone for 30min. Induction of OfJHBP expression by JHA and 20E was significantly greater than that of either hormone alone. These results should contribute to our understanding of how JHBP and JH regulate the termination of larval diapause in the bamboo borer.
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Affiliation(s)
- Eakartit Ritdachyeng
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
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Nilsen KA, Ihle KE, Frederick K, Fondrk MK, Smedal B, Hartfelder K, Amdam GV. Insulin-like peptide genes in honey bee fat body respond differently to manipulation of social behavioral physiology. J Exp Biol 2011; 214:1488-97. [PMID: 21490257 PMCID: PMC3076075 DOI: 10.1242/jeb.050393] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2011] [Indexed: 01/30/2023]
Abstract
Nutrient sensitive insulin-like peptides (ILPs) have profound effects on invertebrate metabolism, nutrient storage, fertility and aging. Many insects transcribe ILPs in specialized neurosecretory cells at changing levels correlated with life history. However, the major site of insect metabolism and nutrient storage is not the brain, but rather the fat body, where functions of ILP expression are rarely studied and poorly understood. Fat body is analogous to mammalian liver and adipose tissue, with nutrient stores that often correlate with behavior. We used the honey bee (Apis mellifera), an insect with complex behavior, to test whether ILP genes in fat body respond to experimentally induced changes of behavioral physiology. Honey bee fat body influences endocrine state and behavior by secreting the yolk protein precursor vitellogenin (Vg), which suppresses lipophilic juvenile hormone and social foraging behavior. In a two-factorial experiment, we used RNA interference (RNAi)-mediated vg gene knockdown and amino acid nutrient enrichment of hemolymph (blood) to perturb this regulatory module. We document factor-specific changes in fat body ilp1 and ilp2 mRNA, the bee's ILP-encoding genes, and confirm that our protocol affects social behavior. We show that ilp1 and ilp2 are regulated independently and differently and diverge in their specific expression-localization between fat body oenocyte and trophocyte cells. Insect ilp functions may be better understood by broadening research to account for expression in fat body and not only brain.
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Affiliation(s)
- Kari-Anne Nilsen
- University of Life Sciences, Department of Chemistry, Biotechnology and Food Science, N-1432 Aas, Norway
| | - Kate E. Ihle
- Arizona State University, School of Life Sciences, Tempe, AZ 85287, USA
| | - Katy Frederick
- Arizona State University, School of Life Sciences, Tempe, AZ 85287, USA
| | - M. Kim Fondrk
- Arizona State University, School of Life Sciences, Tempe, AZ 85287, USA
| | - Bente Smedal
- University of Life Sciences, Department of Chemistry, Biotechnology and Food Science, N-1432 Aas, Norway
| | - Klaus Hartfelder
- Universidade de Sao Paulo, Faculade de Medicina de Ribeirao Petro, 14049-900 Ribeirão Preto, Brazil
| | - Gro V. Amdam
- University of Life Sciences, Department of Chemistry, Biotechnology and Food Science, N-1432 Aas, Norway
- Arizona State University, School of Life Sciences, Tempe, AZ 85287, USA
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Niewiadomska-Cimicka A, Schmidt M, Ożyhar A, Jones D, Jones G, Kochman M. Juvenile hormone binding protein core promoter is TATA-driven with a suppressory element. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1809:226-35. [DOI: 10.1016/j.bbagrm.2011.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 01/10/2011] [Accepted: 02/05/2011] [Indexed: 11/29/2022]
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Sok AJ, Andruszewska G, Niewiadomska-Cimicka A, Grad I, Rymarczyk G, Pajdzik D, Orłowski M, Schmidt MT, Grajek W, Ożyhar A, Kochman M. Regulatory elements in the juvenile hormone binding protein gene from Galleria mellonella — Topography of binding sites for Usp and EcRDBD. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2008; 1779:390-401. [DOI: 10.1016/j.bbagrm.2008.04.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 04/12/2008] [Accepted: 04/29/2008] [Indexed: 11/16/2022]
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Tawfik AI, Kellner R, Hoffmann KH, Lorenz MW. Purification, characterisation and titre of the haemolymph juvenile hormone binding proteins from Schistocerca gregaria and Gryllus bimaculatus. JOURNAL OF INSECT PHYSIOLOGY 2006; 52:255-68. [PMID: 16384579 DOI: 10.1016/j.jinsphys.2005.11.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2005] [Revised: 11/14/2005] [Accepted: 11/14/2005] [Indexed: 05/05/2023]
Abstract
Juvenile hormone binding proteins (JHBPs) were extracted from the haemolymph of adult desert locusts, Schistocerca gregaria, and Mediterranean field crickets, Gryllus bimaculatus. The JHBPs were purified by polyethyleneglycol precipitation, filtration through molecular weight cut off filters and chromatography on a HiTrap heparin column. The juvenile hormone (JH) binding activity of the extracts was measured using a hydroxyapatite assay and the purification progress was monitored by native gel chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The haemolymph JHBPs of both insects are hexamers composed of seemingly identical subunits. The JHBP of the locust has a native Mr of 480 kDa with subunits of 77 kDa, whereas the JHBP of the cricket has a Mr of 510 kDa with subunits of 81 kDa. The locust JHBP binds JH III with moderate affinity (KD = 19 nM). Competition for binding of JH II and JH I was about 2 and 5 times less, respectively. The cricket JHBP also has a moderate affinity for JH III (KD = 28 nM), but surprisingly, competition for binding of JH II was equal to that of JH III and JH I competed about 3 times higher. No sequence information was obtained for the locust JHBP, but the N-terminal sequence of the cricket JHBP shows ca. 56% sequence homology with a hexamerin from Calliphora vicina. Antisera raised against the purified JHBPs were used to measure age- and sex-dependent changes in haemolymph JHBP titres and to confirm that the JHBPs of both species are immunologically different.
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Affiliation(s)
- Amer I Tawfik
- Department of Zoology/Entomology, Faculty of Science, Assiut University, Assiut 71516, Egypt
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Sok AJ, Czajewska K, Ozyhar A, Kochman M. The structure of the juvenile hormone binding protein gene from Galleria mellonella. Biol Chem 2005; 386:1-10. [PMID: 15843141 DOI: 10.1515/bc.2005.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractJuvenile hormone (JH) and ecdysone are the key hormones controlling insect growth and development. The juvenile hormone binding protein (JHBP) is the first member in the array of proteins participating in JH signal transmission. In the present report a wholejhbpgene sequence (9790 bp) is described. Thejhbpgene contains four introns (A–D). All the introns have common flanking sequences: GT at the 5′ and AG at the 3′ end. The first intron is in phase 1, the second in phase 2, and the third and fourth in phase 1. An analysis of these sequences suggests that U2-class spliceosomes are involved in intron excision from pre-mRNA. Several horizontally transmitted elements from other genes were found in the introns. Alljhbpexons are positioned in local AT-reach regions of the gene. A search for core promoter regulatory elements revealed that the TATA box starts 29 bp preceding the start of transcription; the sequence TCAGTA representing a putative initiator sequence (Inr) starts at position +14. Eight characteristic sequences for bindingBroad-Complexgene products, which coordinate the ecdysone temporal response, are present in the non-coding sequence of thejhbpgene. An analysis of exon locations and intron phases indicates thatjhbpgene organization is related to theretinol binding proteingene, a member of the lipocalin family.
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Affiliation(s)
- Agnieszka J Sok
- Division of Biochemistry, Institute of Organic Chemistry, Biochemistry and Biotechnology, Wrocław University of Technology, Wybrzeze Wyspiańskiego 27, 50-370 Wrocław, Poland
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Orth AP, Tauchman SJ, Doll SC, Goodman WG. Embryonic expression of juvenile hormone binding protein and its relationship to the toxic effects of juvenile hormone in Manduca sexta. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2003; 33:1275-1284. [PMID: 14599499 DOI: 10.1016/j.ibmb.2003.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The juvenile hormones (JHs) regulate a diverse array of insect developmental and reproductive processes. One molecular target of JH action is its transporter, hemolymph JH binding protein (hJHBP); in the larva of the tobacco hornworm, Manduca sexta, low doses of JH can immediately increase hJHBP gene expression. Less explored are the effects of JH on embryological development, where early hormonal treatment has been shown to affect embryonic development and pupation. This study examines the egg form of JHBP and its gene expression during embryogenesis of M. sexta, as well as the phenotypic effect JH treatment has on embryos and on JHBP gene expression. We here demonstrate that the preponderance of JHBP found in the egg is maternally derived and that the embryonic gene and protein appear identical to those found in the larva. Expression of the JHBP gene begins in both the embryo itself and extra-embryonic tissues 15 h after fertilization, long before emergence of a functional fat body and circulatory system. Topical application of low JH doses to early embryos resulted in larval abnormalities while high doses of the hormone induced embryonic mortality. These effects are not mediated through regulation of the JHBP gene, since embryonic expression appears invariant in response to JH challenge. The toxicity of JH is tightly correlated with the concentration of unbound hormone.
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Affiliation(s)
- Anthony P Orth
- Department of Entomology, University of Wisconsin-Madison, 237 Russell Labs, 1630 Linden Drive, Madison, WI 53706, USA
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