ABSTRACT
Best macular dystrophy (BMD) is an autosomal dominant human disease characterized by macular degeneration with juvenile onset (OMIM 153700). The disease is most often associated with mutations in Bestrophin, which encodes a novel protein with four putative transmembrane domains. However, complete loss-of-function mutations in Bestrophin have not been reported in humans or mice. We have identified three homologs of human Bestrophin in the Drosophila genome (dbest1-3). The protein products of these three genes share significant homology to a 364 amino acid N-terminal domain of human Bestrophin. We used P-element mutagenesis to delete dbest1, which encodes a protein with the highest amino acid similarity to Bestrophin. Three independent dbest1 mutants were recovered from the mutagenesis screen. Homozygous null mutations in dbest1 do not significantly alter the viability or fertility of mutant flies. Moreover, dbest1 mutants have normal photoreceptor morphology and function.
Subject(s)
Drosophila melanogaster/physiology , Eye Proteins/physiology , Photoreceptor Cells, Invertebrate/physiology , Amino Acid Sequence , Animals , Bestrophins , Blotting, Northern , Chloride Channels , DNA Primers/chemistry , Electroretinography , Eye Proteins/chemistry , Gene Expression Regulation, Developmental , Humans , Macular Degeneration/genetics , Macular Degeneration/physiopathology , Molecular Sequence Data , Mutation , RNA, Messenger/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Sequence Homology, Amino AcidABSTRACT
Balancer chromosomes are genetic reagents that are used in Drosophila melanogaster for stock maintenance and mutagenesis screens. Despite their utility, balancer chromosomes are rarely used in mice because they are difficult to generate using conventional methods. Here we describe the engineering of a mouse balancer chromosome with the Cre-loxP recombination system. The chromosome features a 24-centiMorgan (cM) inversion between Trp53 (also known as p53) and Wnt3 on mouse chromosome 11 that is recessive lethal and dominantly marked with a K14-Agouti transgene. When allelic to a wild-type chromosome, the inversion suppresses crossing over in the inversion interval, accompanied by elevated recombination in the flanking regions. The inversion functions as a balancer chromosome because it can be used to maintain a lethal mutation in the inversion interval as a self-sustaining trans-heterozygous stock. This strategy can be used to generate similar genetic reagents throughout the mouse genome. Engineering of visibly marked inversions and deficiencies is an important step toward functional analyses of the mouse genome and will facilitate large-scale mutagenesis programs.