PURPOSE: To obtain the subject new membranous protein useful for research, etc., on telencephalon functions by inserting a telencephalon-specific membranous protein telencephalin cDNA sorted out of a mammalian telencephalon cDNA library into an expression vector and carrying out the gene expression in a host cell.

CONSTITUTION: This telencephalon-specific membranous protein telencephalin is obtained by screening a telencephalon cDNA library of a mammal (e.g. a rabbit) according to the cross hybridization using a probe based on a nucleotide sequence capable of coding a telencephalon-specific membranous protein telencephalin and affording a cDNA capable of coding the telencephalon-specific membranous protein telencephalin of the mammal, then treating the resultant cDNA with a restriction enzyme, joining the obtained DNA to a suitable expression vector, preparing a recombinant DNA, inserting the resultant recombinant DNA into a host cell (e.g. CDS7 cell), transforming the host cell and subsequently culturing the transformed host cell. Thereby, the resultant telencephalon- specific membranous protein telencephalin derived from the mammal participates in the formation of an interneuronal network.