title: Chromosome puff activity and protein synthesis in larval salivary glands of Drosophila melanogaster.
abstract: Secretion proteins from larval salivary glands of Drosophila melanogaster were analyzed with acrylamide gel electrophoresis. Four fractions were found; three showed electrophoretic variants in different wild-type stocks. Crossbreeding and cytogenetic techniques were used to localize the genes responsible for the two main fractions: The gene for fraction 3 was found to lie within a segment of the third chromosome which includes section 68C; the gene for fraction 4, Sgs-4, was found to lie within section 3C8-3D1 of the X chromosome (1 - 3-5). The puffs within these sections of the giant chromosomes are active before and during secretion synthesis and become inactive as secretion synthesis ceases. Larvae of one wild-type stock which lack protein fraction 4 do not exhibit any puffing in 3C. The relative amount of protein 4 in the salivary secretion shows a marked dependence on the dosage of the Sgs-4 gene in both duplication and deficiency genotypes. The active site within puff 3C11-12 apparently contains the structural gene for protein 4.
mesh_terms: D002874:Chromosome Mapping; D002875:Chromosomes / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000378:metabolism*; D005796:Genes; D007814:Larva; D014176:Protein Biosynthesis; D011506:Proteins / Q000378:metabolism; D011995:Recombination, Genetic; D012463:Saliva; D012469:Salivary Glands / Q000378:metabolism / Q000648:ultrastructure; D012730:Sex Chromosomes; D012737:Sex Factors
chemical_list: D011506:Proteins