dbest1, a Drosophila homolog of human Bestrophin, is not required for viability or photoreceptor integrity

Best macular dystrophy (BMD) is an autosomal dominant human disease charact erized by macular degeneration with juvenile onset (OMIM 153700). The disea se is most often associated with mutations in Bestrophin, which encodes a n ovel protein with four putative transmembrane domains. However, complete lo ss-of-function mutations in Bestrophin have not been reported in humans or mice. We have identified three homologs of human Bestrophin in the Drosophi la genome (dbest1-3). The protein products of these three genes share signi ficant homology to a 364 amino acid N-terminal domain of human Bestrophin. We used P-element mutagenesis to delete dbest1, which encodes a protein wit h the highest amino acid similarity to Bestrophin. Three independent dbest1 mutants were recovered from the mutagenesis screen. Homozygous null mutati ons in dbest1 do not significantly alter the viability or fertility of muta nt flies. Moreover, dbest1 mutants have normal photoreceptor morphology and function. (C) 2001 Wiley-Liss, Inc.