The mouse Ptprr gene encodes two protein tyrosine phosphatases, PTP-SL and PTPBR7, that display distinct patterns of expression during neural development.
The protein tyrosine phosphatases PTP-SL and PTPBR7 differ only in the length of their N-terminal domain. We show here that PTP-SL and PTPBR7 are isoforms derived from a single gene (Ptprr) through developmentally regulated use of alternative promoters. Isoform-specific reverse transcriptase-polymer chain reaction (RT-PCR) and RNA in situ hybridization experiments reveal that PTPBR7 is expressed during early embryogenesis in spinal ganglia cells as well as in developing Purkinje cells. Post-natally, PTPBR7 is expressed in various regions of the adult mouse brain, but expression in Purkinje cells has ceased and is replaced by the PTP-SL-specific transcript. In transient transfection experiments it is confirmed that PTPBR7 is a type I transmembrane protein tyrosine phosphatase (PTPase). PTP-SL, however, appears to be a cytosolic membrane-associated PTPase that is located at perinuclear vesicular structures that partly belong to the endosomal compartment. Thus, during maturation of Purkinje cells, a gene-promoter switch results in the replacement of a receptor-type PTPase by a cytosolic vesicle-associated isoform.
Van Den Maagdenberg
A M
AM
Department of Cell Biology, Institute of Ceullular Signalling, University of Nijmegen, The Netherlands.
Bächner
D
D
Schepens
J T
JT
Peters
W
W
Fransen
J A
JA
Wieringa
B
B
Hendriks
W J
WJ
D000375:Aging; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D001921:Brain / Q000196:embryology / Q000201:enzymology* / Q000254:growth & development; D019556:COS Cells; D005314:Embryonic and Fetal Development; D004705:Endocytosis; D005727:Ganglia, Spinal / Q000196:embryology / Q000201:enzymology / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D005865:Gestational Age; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics*; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D011689:Purkinje Cells / Q000201:enzymology; D054634:Receptor-Like Protein Tyrosine Phosphatases, Class 7; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D014162:Transfection
D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; D017027:Protein Tyrosine Phosphatases; C513472:Ptprr protein, mouse; D054634:Receptor-Like Protein Tyrosine Phosphatases, Class 7