Organization and alternate splice products of the gene encoding nuclear inhibitor of protein phosphatase-1 (NIPP-1).
Nuclear inhibitor of protein phosphatase-1 (NIPP-1) is one of two major regulatory subunits of protein phosphatase-1 in mammalian nuclei. We report here the cloning and structural characterization of the human NIPP-1 genes, designated PPP1R8P and PPP1R8 in human gene nomenclature. PPP1R8P (1.2 kb) is a processed pseudogene and was localized by in situ hybridization to chromosome 1p33-32. PPP1R8 is an authentic NIPP-1 gene and was localized to chromosome 1p35. PPP1R8 (25.2 kb) is composed of seven exons and encodes four different transcripts, as determined from cDNA library screening, reverse transcriptase-PCR (RT-PCR) and/or EST (expressed sequence tag) database search analysis. NIPP-1alpha mRNA represents the major transcript in human tissues and various cell lines, and encodes a polypeptide of 351 residues that only differs from the previously cloned calf thymus NIPP-1 by a single residue. The other transcripts, termed NIPP-1beta, gamma and delta, are generated by alternative 5'-splice site usage, by exon skipping and/or by alternative polyadenylation. The NIPP-1beta/delta and NIPP-1gamma mRNAs are expected to encode fragments of NIPP-1alpha that differ from the latter by the absence of the first 142 and 224 residues, respectively. NIPP-1gamma corresponds to 'activator of RNA decay-1' (Ard-1) which, unlike NIPP-1alpha, displays in vitro and endoribonuclease activity and lacks an RVXF consensus motif for interaction with protein phosphatase-1. While the NIPP-1alpha/beta/delta-transcripts were found to be present in various human tissues, the NIPP-1gamma transcript could only be detected in human transformed B-lymphocytes.
Van Eynde
A
A
Afdeling Biochemie, Campus Gasthuisberg KULeuven, Herestraat 49, B-3000 Leuven, Belgium.
Pérez-Callejón
E
E
Schoenmakers
E
E
Jacquemin
M
M
Stalmans
W
W
Bollen
M
M
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins; D002460:Cell Line; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004722:Endoribonucleases; D004791:Enzyme Inhibitors / Q000378:metabolism*; D006801:Humans; D006822:Hybrid Cells; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010749:Phosphoprotein Phosphatases; D010765:Phosphorylase Phosphatase / Q000037:antagonists & inhibitors*; D054645:Protein Phosphatase 1; D011544:Pseudogenes; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014018:Tissue Distribution
D002352:Carrier Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C021042:protein phosphatase inhibitor-1; D004722:Endoribonucleases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D010765:Phosphorylase Phosphatase; C097081:PPP1R8 protein, human