MOLECULAR STUDIES OF DROSOPHILA PHOTORECEPTORS: I. IDENTIFICATION AND BIOCHEMICAL CHARACTERIZATION OF DROSOPHILA MELANOGASTER RHODOPSIN. II. CYTOLOGICAL LOCALIZATION AND PRELIMINARY BIOCHEMICAL STUDIES OF THE NORPA GENE. APPENDIX: VITAMIN A DEPRIVATION OF DROSOPHILA: A SIMPLE, RELIABLE RECIPE

RUTHANN NICHOLS, Purdue University

Abstract

Rhodopsin from the peripheral photoreceptors (R1-6) of Drosophila melanogaster has been studied. Based on five defining criteria a polypeptide present in a two dimensional electrophoretic separation of a Drosophila eye homogenate has been identified as opsin. The opsin polypeptide is absent in the silver stained two dimensional electrophoretic pattern of the Drosophila mutant, ora('JK84). The concentration of opsin is reduced in vitamin A deprived wild type. Vitamin A deprivation of Drosophila melanogaster can be achieved by raising adult flies on a simple, reliable medium. The use of this diet has numerous advantages over vitamin A deficient synthetic media. This diet is a simple, reliable medium containing no antibiotics or mold inhibitors and no mold or bacterial growth. The flies raised on this medium are well deprived of vitamin A as determined by pseudopupil, electroretinogram, microspectrophotometric and M(,1)-potential analyses. The temperature sensitive electroretinogram response of the visually defective Drosophila mutant, norpA('H52), was characterized. Two dimensional electrophoretic gel patterns of norpA('H52) and wild-type eye homogenates prepared at permissive and non-permissive temperatures identified a putative norpA gene product. This polypeptide (approximate pI, 7; approximate MW, 18,000 daltons) was present in the norpA('H52) gel pattern at permissive temperatures but absent at non-permissive temperatures. The norpA gene was cytologically localized using deletion and translocation stocks to 4B1-4C1,3 on the X chromosome.

Degree

Ph.D.

Subject Area

Biology

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