Molecular cloning and tissue-specific RNA processing of a murine receptor-type protein tyrosine phosphatase.
The molecular cloning of a murine receptor-type protein tyrosine phosphatase, termed PTP NU-3, with an extracellular cell-adhesion-molecule-like domain is reported. NU-3 was isolated from 11.5-day total mouse embryonic RNA by reverse-transcriptase PCR using degenerate oligonucleotides flanking the conserved protein tyrosine phosphatase catalytic domain. This produced a 280-bp DNA probe which was subsequently employed to screen a mouse embryonic kidney library. Several overlapping cDNA clones were isolated, collectively forming a cDNA of 6.0 kb that encodes a putative 211-kDa protein. Northern-blot analysis of total RNA from adult and embryonic mouse tissues indicates the existence of two major PTP NU-3 transcripts of approximately 6 kb and 7 kb. Both messages are expressed predominantly in brain tissues and neuronal-derived cell lines, although detectable levels of the 7-kb message were found in other non-neuronal tissues. We have identified a unique 132-bp exon segment that is present in the 7-kb message but is completely absent in the 6-kb transcript, suggesting tissue-specific levels of expression and RNA processing. Analysis of the amino acid sequence encoded by the 132-bp segment reveals that it completes a partial fibronectin type-III element resulting in a protein with a total of nine such elements. Bacterial expression of the two catalytic domains demonstrated that only the first domain possesses enzymic activity towards a tyrosine phosphorylated substrate.
Wagner
J
J
McGill University, Department of Biochemistry, Montreal, Quebec, Canada.
Boerboom
D
D
Tremblay
M L
ML
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D015342:DNA Probes; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004622:Embryo, Mammalian; D015870:Gene Expression; D007668:Kidney; D051379:Mice; D008969:Molecular Sequence Data; D019000:Phosphotyrosine; D016133:Polymerase Chain Reaction; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012313:RNA / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D012194:RNA-Directed DNA Polymerase; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2; D011994:Recombinant Proteins / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
D015342:DNA Probes; D018076:DNA, Complementary; D012333:RNA, Messenger; D011994:Recombinant Proteins; D019000:Phosphotyrosine; D014443:Tyrosine; D012313:RNA; D012194:RNA-Directed DNA Polymerase; D017027:Protein Tyrosine Phosphatases; C516885:Ptprs protein, mouse; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2