A DROSOPHILA LOCUS WITH GENE DOSAGE EFFECTS ON RHODOPSIN
Abstract
Mutations that decrease the amplitude of the prolonged depolarizing after potential (PDA) in Drosophila melanogaster have previously been shown to have reduced rhodopsin content in the rhabdomeres of photoreceptor cells. In the present study, a genetic analysis of a class of third chromosome PDA-defective mutants localized the ninaE locus (3-66) to the salivary band region 92A-92B. When this region is present in only one dose, and in ninaE heterozygotes, the rhodopsin content of the major class of photoreceptors is reduced. Three doses of this region increases the rhodopsin content of these photoreceptors. These characteristics of the ninaE locus are expected of the structural gene encoding the major species of opsin in the Drosophila compound eye. In addition to the genetic analysis of the ninaE mutants, two-dimensional gel patterns of mutant and wild-type flies were compared. While no major differences in the number and quality of retina-specific polypeptides were observed between mutant and wild-type flies, the behavior of retina-specific light modified polypeptides was observed to differ in homozygous and heterozygous mutant flies when compared to wild-type flies. During the course of this biochemical analysis, an attempt was made to genetically localize an eye-specific isoelectric point variant which was considered to be a good candidate for opsin on the two-dimensional gel.
Degree
Ph.D.
Subject Area
Anatomy & physiology|Animals
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