Genomic organization of the hamster phospholipase C-delta 1 gene: differential loss of separate alleles of the phospholipase C-delta 1 gene in two fibroblast mutants lacking phospholipase C-delta 1.

In earlier work from this laboratory, mutant Chinese hamster lung fibroblasts D1-6b and D1-9b were shown to lack phosphatidylinositol-specific phospholipase C-delta 1 (PLC delta 1). In the current study, Northern analysis of mRNA samples from these mutants fails to detect full-length transcripts for PLC delta 1. Southern analysis of Sac1 digests of wild type and mutant cell genomic DNA hybridized against probe made to full-length rat brain PLC delta 1 cDNA suggested that these mutants differ from one another and wild type controls. This observation is shown to be the result of the differential loss, in both mutants, of one of two alleles for the hamster PLC delta 1 gene normally present in the parental cell line. During the course of these studies, the hamster PLC delta 1 gene was cloned and sequenced. This genomic sequence spans 13 kb of DNA and encoded 98.5% of the predicted coding sequence for the hamster PLC delta 1 cDNA within 15+ exons.