THE RAB PROTEIN FAMILY - GENETIC-MAPPING OF 6 RAB GENES IN THE MOUSE

Rab proteins constitute a family of GTP-binding proteins that are loca ted in distinct intracellular compartments and play a role in the regu lation of vesicular trafficking. Yeast mutations in Rab gene homologs cause defects in vesicular transport similar to those observed in beig e (bg) mice. To investigate Rob genes as candidates for mouse mutation s characterized by defects in vesicular trafficking, we utilized an in ter-subspecific backcross [C57BL/6J-bg(J) x (C57BL/6J-bg(J) x CAST/Ei) F-1] segregating for the bg locus. Restriction fragment length polymor phisms (RFLPs) were obtained through Southern hybridization of F-1 and C57BL/6J chromosomal DNA with the coding sequences of Rab genes. Thes e RFLPs and 12 polymorphic microsatellites were used to determine the segregation of the Rab genes in 93 backcross mice. Rab4a, Rab4b, Rab7, Rab10, Rab22, and Rab24 were localized on mouse chromosomes 8, 7, 9, 12, 2, and 13, respectively. Although the results exclude these loci a s candidates for bg, they demonstrate a wide dispersion of Rob genes t hroughout the mouse genome and reveal that Rab4b and Rab24 are possibl e candidates for the mouse mutations reduced pigmentation (rp) and pur kinje cell degeneration (pcd), respectively. (C) 1995 Academic Press, Inc.