NUCLEOTIDE-SEQUENCE AND MOLECULAR VARIANTS OF RAT RECEPTOR-TYPE PROTEIN-TYROSINE PHOSPHATASE-XI BETA/

We have previously described the cloning of phosphacan, a chondroitin sulfate proteoglycan of nervous tissue which interacts with neurons, g lia, neural cell adhesion molecules, and tenascin, and represents the extracellular domain of a receptor-type protein tyrosine phosphatase. We now report the complete cDNA and deduced amino acid sequences of th e rat transmembrane phosphatase, and demonstrate that the phosphatase and the extracellular proteoglycan have different 3'-untranslated regi ons. Northern analysis showed three probable splice variants, comprisi ng the extracellular proteoglycan (phosphacan) and long and short form s of the transmembrane phosphatase. PCR studies of rat genomic DNA ind icated that there are no introns at the putative 5' and 3' splice site s or in the 2.6 kb segment which is deleted in the short transmembrane protein. Using variant-specific riboprobes corresponding to sequences in the 3'-untranslated region of phosphacan and in the first or secon d phosphatase domains of the transmembrane protein, in site hybridizat ion histochemistry of embryonic rat brain and spinal cord and early po stnatal cerebellum demonstrated identical localizations of phosphacan and phosphatase mRNAs.