Molecular cloning of Drosophila Rh6 rhodopsin: the visual pigment of a subset of R8 photoreceptor cells 1

• Published in: FEBS letters 1997-04, Vol.406 (1-2), p.6-10
• Main Authors: Huber, Armin, Schulz, Simone, Bentrop, Joachim, Groell, Christine, Wolfrum, Uwe, Paulsen, Reinhard
• Format: Article
• Language: English
• Subjects: Drosophila; G-protein; Phototransduction; Rhodopsin; Vision; Visual pigment
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(97)00210-X

By screening retinal cDNA libraries for photoreceptor‐specifically expressed genes we have isolated and sequenced a cDNA clone encoding the rhodopsin (Rh6) of a subset of R8 photoreceptor cells of the Drosophila compound eye. Compared to the other visual pigments of Drosophila, this rhodopsin is equally homologous to Rh1 and Rh2 (51% amino acid identity) but shows only 32% and 33% amino acid identity with Rh3 and Rh4, respectively. The open reading frame codes for a protein of 369 amino acids (MW=41 691). The primary structure of Rh6 displays sites typical for rhodopsin molecules in general, for example, a chromophore binding site in transmembrane domain VII, sequence motifs in the intracellular loops 2 and 3 required for the binding of a heterotrimeric G‐protein, and a glycosylation site near the N‐terminus which seems to be important for protein transport and maturation. Since R8 cells are founder cells in the developing compound eye, the isolation of a rhodopsin gene expressed in these cells may aid the understanding of terminal differentiation of photoreceptor cells.