title: The induction of DNA puff BhC4-1 gene is a late response to the increase in 20-hydroxyecdysone titers in last instar dipteran larvae.
abstract: The characterization of DNA puff BhC4-1 expression was extended and its response to 20-hydroxyecdysone investigated in Bradysia hygida and in transgenic Drosophila carrying the BhC4-1 gene. In both organisms the activation of BhC4-1 in salivary glands occurs at the end of the larval stage coinciding with the peak in ecdysone titers which induces metamorphosis. Injections of 20-hydroxyecdysone into mid-fourth instar larvae of B. hygida show that the induction of BhC4-1 expression, as well as amplification and puff C4 expansion, are late events induced by the hormone. This late response of BhC4-1 expression was also observed in transgenic salivary glands cultivated in the presence of 20-hydroxyecdysone. In vitro studies using transgenic Drosophila indicate that both repressor and activator factors regulate the timing of BhC4-1 expression in salivary glands.
authors.affiliation: Departamento de Biologia Celular, Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3.900, Ribeirão Preto 14049-900, SP, Brazil.
authors.forename: L R
authors.initials: LR
authors.lastname: Basso
authors.forename: C
authors.initials: C
authors.lastname: Vasconcelos
authors.forename: A M
authors.initials: AM
authors.lastname: Fontes
authors.forename: K
authors.initials: K
authors.lastname: Hartfelder
authors.forename: J A
authors.initials: JA
authors.lastname: Silva
authors.forename: P S R
authors.initials: PS
authors.lastname: Coelho
authors.forename: N
authors.initials: N
authors.lastname: Monesi
authors.forename: M L
authors.initials: ML
authors.lastname: Paçó-Larson
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002875:Chromosomes / Q000187:drug effects / Q000648:ultrastructure; D004175:Diptera / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D004330:Drosophila / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics; D004441:Ecdysterone / Q000378:metabolism / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D017344:Genes, Insect / Q000187:drug effects; D006458:Hemolymph / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics*; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D012469:Salivary Glands / Q000187:drug effects / Q000648:ultrastructure; D012471:Salivary Proteins and Peptides / Q000235:genetics*
chemical_list: D029721:Drosophila Proteins; D019476:Insect Proteins; D012471:Salivary Proteins and Peptides; C095605:puff C4 protein, Bradysia hygida; D004441:Ecdysterone