RHODOPSIN PLAYS AN ESSENTIAL STRUCTURAL ROLE IN DROSOPHILA PHOTORECEPTOR DEVELOPMENT

Null mutations of the Drosophila Rh1 rhodopsin gene, ninaE, result in developmental defects in the photosensitive membranes, the rhabdomeres , of compound eye photoreceptors R1-R6. In normal flies, Rh1 expressio n begins at about 78% of pupal life, At approximately 90% of pupal lif e, a specialized catacomb-like membrane architecture develops at the b ase of normal rhabdomeres. In ninaE null mutants, these catacombs do n ot form and developing rhabdomere membrane involutes into the cell as curtains of apposed plasma membrane. A filamentous cytoskeletal comple x that includes F-actin and the unconventional myosin, NINAC, decorate s the cytoplasmic surface of these curtains.