Molecular approaches towards the isolation of tyrosine phosphatases expressed in the peripheral nervous system

Protein tyrosine phosphatases (PTP) are increasingly appreciated to play a crucial function in the development, homeostasis and regeneration of the nervous system. In an attempt to determine the set of PTPs that are expressed in the PNS, we have employed polymerase chain reaction (PCR)-based strategies. Degenerate oligonucleotide primers which were designed based on PTP-consensus motifs were used on substrate cDNAs derived from sciatic nerves of either 3, 10 or 60 days-old rats as well as from cultured rat Schwann cells. The resulting partial PTP clones were used for low-stringency hybridization screening of a cDNA library constructed from the sciatic nerves of 7 to 8 days-old rats. The combined approaches yielded three known rat PTPs and at least three potential rat species homologues of previously identified mouse PTPs. Furthermore, several partial clones encoding potentially novel PTPs have been isolated. The suitability of our experimental approaches for the identification and characterization of PNS-expressed PTPs will be discussed.