MOLECULAR-CLONING AND CHARACTERIZATION OF MAMMALIAN HOMOLOGS OF THE DROSOPHILA RETINAL DEGENERATION B-GENE

Null mutations in the retinal degeneration B gene (rdgB) in flies resu lt in an activity-dependent retinal degeneration. Here we report the i solation of the mouse and human homologues of rcEgB gene that are stro ngly expressed in brain and moderately expressed in other tissues. The deduced amino acid sequences encoding a 1244 a.a protein bear a 96% s imilarity between mouse and human and resemble the Drosophila rdgB, pa rticularly in the phosphatidylinositol transfer domain at the N-termin us and in six putative transmembrane domains at the C-terminus. Immuno blots with antiserum raised against a bacterially expressed fragment o f the mouse rdgB showed the band with a molecular weight of about 170 kDa. Interestingly, a burst of mouse rdgB expression occurs on 17th da y of gestation, suggesting a crucial role of the gene product in brain development at this particular stage. A gene, mpt-1, encoding for mou se rdgB was mapped to the proximal end of chromosome 19, which is the same location as Mvb-1, a gene locus encoding tile modifier of mouse v ibrator mutation (mv). (C) 1997 Academic Press.