title: Distinct roles of Broad isoforms in regulation of the 20-hydroxyecdysone effector gene, Vitellogenin, in the mosquito Aedes aegypti.
abstract: We investigated the role of the mosquito broad (br) gene in regulating the 20-hydroxyecdysone (20E) effector Vitellogenin (Vg) gene. Injection of double-stranded RNA corresponding to the BR isoform Z2 led to a significant decrease in expression of the Vg gene at 8 and 24h post-blood meal. Knockdown of Z1 or Z4 resulted in enhanced Vg expression beyond its normal expression time. In vitro studies suggested that the effects of BR require its direct binding to the Vg promoter, as well as protein-protein interaction between BR and the ecdysone receptor complex. The BR isoforms are therefore essential for a proper stage-specific biological response to 20E in the adult female mosquito. In particular, the isoform Z2 is required for 20E-mediated activation of Vg, while isoforms Z1 and Z4 serve as repressors to ensure appropriate termination of Vg expression.
authors.affiliation: Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA.
authors.forename: Jinsong
authors.initials: J
authors.lastname: Zhu
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Raikhel
mesh_terms: D000330:Aedes / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins; D004331:Drosophila melanogaster; D004441:Ecdysterone / Q000378:metabolism*; D005216:Fat Body; D005247:Feeding Behavior; D005260:Female; D005786:Gene Expression Regulation; D019476:Insect Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D051381:Rats; D011987:Receptors, Steroid / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014819:Vitellogenins / Q000235:genetics* / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D020033:Protein Isoforms; D011987:Receptors, Steroid; D014157:Transcription Factors; C066030:USP protein, Drosophila; D014819:Vitellogenins; C055469:ecdysone receptor; D004441:Ecdysterone