PURPOSE: To obtain a DNA sequence coding a mouse receptor-type tyrosine phosphatase expressing in a localized region of central nervous system and in the immunity system and giving an antibody useful for the clarification of the intracellular information transmission mechanism and regulation mechanisms of nervous system and immunity system.

CONSTITUTION: This DNA sequence coding a mouse receptor-type tyrosine phosphatase MPTPδ and giving an antibody useful for the clarification of the molecular mechanism of intracellular information transmission, regulation mechanisms of nervous system and immunity system and the mechanism of tumorigenesis can be produced by preparing about 1,000,000 plaques with a mouse brain cDNA library, transferring the plaques to a nylon film, screening by the hybridization reaction with a sequence common to a tyrosine phosphatase (PTP) labeled with 32P to select a positive plaque, treating the nylon film with a solution containing a surfactant to separate the DNA from the reacting plaque and finally treating the DNA with restriction enzymes.