GENOMIC ORGANIZATION AND FUNCTIONAL-ANALYSIS OF THE MURINE PROTEIN PHOSPHATASE 1C-GAMMA (PPP1CC) GENE

Protein phosphatase 1 holoenzymes are composed of catalytic subunits i n combination with various regulatory subunits. In rodents, four diffe rent catalytic isoforms are known, PP1c alpha, -delta, -gamma 1, and - gamma 2. Here we describe the genomic organization of the murine Ppp1c c gene that encodes the PP1c gamma 1 and PP1c gamma 2 isoforms. We det ermined that Ppp1cc maps to F1.2-G1.2 on chromosome 5 by FISH mapping, Southern hybridization and analysis of cross-hybridizing genomic clon es revealed four Ppp1cc-related pseudogenes in the mouse genome. The a uthentic Ppp1cc gene encodes two isoforms, PP1c gamma 1 and PP1c gamma 2, that arise from alternative splicing and differ by retention of th e last intron. The introns of Ppp1cc are flanked by short direct repea ts, the significance of which is not clear. Both isoforms retain phosp hatase function since they are able to complement the cold-sensitive P P1 defect caused by the dis2-11 mutation in the fission yeast Schizosa ccharomyces pombe. (C) 1997 Academic Press.