UC Irvine

The structural gene for human GBA has been assigned to chromosome 1 using somatic cell hybridization techniques for gene mapping. The human enzyme was detected in mouse RAG cell-human fibroblast cell hybrids by a sensitive double antibody immunoprecipitation assay using a mouse anti-human GBA antibody. No cross-reactivity between mouse beta-glucosidase and human GBA or GBN was observed. For the initial assignment, fifty-two primary, secondary, and tertiary man-mouse hybrids lines, derived from three separate fusion experiments, were analyzed for human GBA and enzyme markers for the human chromosomes. Without exception, the presence of human GBA in these hybrid clones was correlated with the presence of human chromosome 1 or its enzymatic markers, PGM1 and FH. All other human chromosomes were eliminated by the independent segregation of GBA and their respective enzyme markers and/or chromosomes. Using a RAG-human fibroblast line with a mouse-human rearrangement of human chromosome 1, the locus for GBA was limited to the region 1p11 leads to 1qter. Further regional localization was obtained using subclones of hybrids derived from the fusion of a human fibroblast line, 46,XX,del(1)(pter leads to q42:), with mouse RAG fibroblasts. All hybrid subclones containing a normal chromosome 1 were positive for GBA. In contrast, subclones with a single deleted chromosome 1 were negative for GBA by immunoprecipitation and by the natural substrate assays. These results further localized the gene for GBA to the narrow region, 1q42 leads to 1qter.