Requirement of N-linked glycosylation site inDrosophilarhodopsin

Abstract

AbstractIn vitromutagenesis and germline transformation were used to create aDrosophilamutant, ΔAsn20lacking the N-linked glycosylation site near the amino terminus of the major rhodopsin (Asn20-Gly-Ser changed to Ile-Gly-Ser). Low opsin protein levels are detected in ΔAsn20photoreceptors. Electroretinogram responses of mutant flies show that the residual rhodopsin found in this mutant is capable of initiating phototransduction. The organization of rhabdomeres, the photoreceptor organelle containing nearly all of the rhodopsin, is aberrant in the ΔAsn20mutant and undergoes age-dependent deterioration. These results establish that an N-linked glycosylation site, and likely glycosylation itself, plays a critical role in the maturation ofDrosophilarhodopsin.