title: Drosophila Met and Gce are partially redundant in transducing juvenile hormone action.
abstract: The Drosophila Methoprene-tolerant (Met) and Germ cell-expressed (Gce) bHLH-PAS transcription factors are products of two paralogous genes. Both proteins potentially mediate the effect of juvenile hormone (JH) as candidate JH receptors. Here we report that Met and Gce are partially redundant in transducing JH action. Both Met and gce null single mutants are fully viable, but the Met gce double mutant, Met(27) gce(2.5k), dies during the larval-pupal transition. Precocious and enhanced caspase-dependent programmed cell death (PCD) appears in fat body cells of Met(27) gce(2.5k) during the early larval stages. Expression of Kr-h1, a JH response gene that inhibits 20-hydroxyecdysone (20E)-induced broad (br) expression, is abolished in Met(27) gce(2.5k) during larval molts. Consequently, expression of br occurs precociously in Met(27) gce(2.5k), which may cause precocious caspase-dependent PCD during the early larval stages. Defective phenotypes and gene expression changes in Met(27) gce(2.5k) double mutants are similar to those found in JH-deficient animals. Importantly, exogenous application of JH agonists rescued the JH-deficient animals but not the Met(27) gce(2.5k) mutants. Our data suggest a model in which Drosophila Met and Gce redundantly transduce JH action to prevent 20E-induced caspase-dependent PCD during larval molts by induction of Kr-h1 expression and inhibition of br expression.
authors.affiliation: Department of Entomology, University of Maryland, College Park, MD 20742, USA.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Abdou
authors.forename: Qianyu
authors.initials: Q
authors.lastname: He
authors.forename: Di
authors.initials: D
authors.lastname: Wen
authors.forename: Ola
authors.initials: O
authors.lastname: Zyaan
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Jinjin
authors.initials: J
authors.lastname: Xu
authors.forename: Aaron A
authors.initials: AA
authors.lastname: Baumann
authors.forename: Justin
authors.initials: J
authors.lastname: Joseph
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Wilson
authors.forename: Sheng
authors.initials: S
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death; D004330:Drosophila / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D005216:Fat Body / Q000502:physiology; D005260:Female; D007605:Juvenile Hormones / Q000378:metabolism*; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism; D008297:Male; D009154:Mutation; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D029721:Drosophila Proteins; D007605:Juvenile Hormones; D051741:Kruppel-Like Transcription Factors; D014157:Transcription Factors; C102117:Br protein, Drosophila; C497242:Kr-h1 protein, Drosophila; C111234:MET protein, Drosophila; C543965:gce protein, Drosophila