title: DNA puff C4 of Bradysia hygida (Diptera: Sciaridae) contains genes unequally amplified and differentially expressed during development.
abstract: We report here the isolation and characterization of a 2.3 kb genomic EcoRI fragment that co-localizes in the DNA puff C4 of Bradysia hygida with a 4 kb EcoRI fragment previously characterized as containing part of a gene amplified and expressed in the salivary gland at the time when puff C4 expands. Verification of the relative amount of DNA complementary to these two genomic fragments shows that they are unequally amplified in the salivary gland. The fragment containing part of the gene expressed when puff C4 expands amplifies about eight times more than the 2.3 kb fragment. This 2.3 kb fragment also carries sequences complementary to RNA species present in the gland in a period when puff C4 has already receded. Based on these data we discuss the nature of the DNA puff and the possible way in which amplification is occurring at these sites.
authors.affiliation: Departamento de Morfologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brasil.
authors.forename: P S
authors.initials: PS
authors.lastname: Coelho
authors.forename: J C
authors.initials: JC
authors.lastname: De Almeida
authors.forename: F
authors.initials: F
authors.lastname: Toledo
authors.forename: G
authors.initials: G
authors.lastname: Buttin
authors.forename: M L
authors.initials: ML
authors.lastname: Paçó-Larson
mesh_terms: D000818:Animals; D015139:Blotting, Southern; D002875:Chromosomes / Q000648:ultrastructure; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D015246:Deoxyribonuclease EcoRI; D004175:Diptera / Q000235:genetics*; D005260:Female; D005784:Gene Amplification; D017404:In Situ Hybridization, Fluorescence; D007814:Larva; D010449:Peptide Mapping; D012313:RNA / Q000302:isolation & purification; D012469:Salivary Glands / Q000166:cytology
chemical_list: D012313:RNA; D004247:DNA; D015246:Deoxyribonuclease EcoRI