title: bHLH-PAS heterodimer of methoprene-tolerant and Cycle mediates circadian expression of juvenile hormone-induced mosquito genes.
abstract: Juvenile hormone (JH) governs a great diversity of processes in insect development and reproduction. It plays a critical role in controlling the gonadotrophic cycles of female mosquitoes by preparing tissues for blood digestion and egg development. Here, we show that in female Aedes aegypti mosquitoes JH III control of gene expression is mediated by a heterodimer of two bHLH-PAS proteins-the JH receptor methoprene-tolerant (MET) and Cycle (CYC, AAEL002049). We identified Aedes CYC as a MET-interacting protein using yeast two-hybrid screening. Binding of CYC and MET required the presence of JH III. In newly eclosed female mosquitoes, the expression of two JH-responsive genes, Kr-h1 and Hairy, was dependent on both the ratio of light to dark periods and JH III. Their expression was compromised by in vivo RNA interference (RNAi) depletions of CYC, MET, and the steroid receptor coactivator SRC/FISC. Moreover, JH III was not effective in induction of Kr-h1 and Hairy gene expression in vitro in fat bodies of female mosquitoes with RNAi-depleted CYC, MET or SRC/FISC. A sequence containing an E-box-like motif from the Aedes Kr-h1 gene promoter specifically interacted with a protein complex, which included MET and CYC from the female mosquito fat body nuclear extract. These results indicate that a MET/CYC heterodimer mediates JH III activation of Kr-h1 and Hairy genes in the context of light-dependent circadian regulation in female mosquitoes during posteclosion development. This study provides an important insight into the understanding of the molecular basis of JH action.
authors.affiliation: Department of Entomology and the Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA.
authors.forename: Sang Woon
authors.initials: SW
authors.lastname: Shin
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zou
authors.forename: Tusar T
authors.initials: TT
authors.lastname: Saha
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Raikhel
mesh_terms: D056930:ARNTL Transcription Factors / Q000235:genetics / Q000378:metabolism; D000330:Aedes / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D002940:Circadian Rhythm / Q000235:genetics*; D024202:Electrophoretic Mobility Shift Assay; D005216:Fat Body / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D019476:Insect Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D007605:Juvenile Hormones / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011485:Protein Binding; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D020798:Two-Hybrid System Techniques
chemical_list: D056930:ARNTL Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D019476:Insect Proteins; D007605:Juvenile Hormones