A member of the ras gene superfamily is expressed specifically in T, B and myeloid hemopoietic cells.

A 1.26 kb murine cDNA having 31% homology with human ras and 55% homology with human rho proteins was isolated using an oligonucleotide probe homologous to catalytic subdomain of a tyrosine kinase subfamily. Northern blot analysis indicates that the expression of the murine gene is restricted to the cells of hemopoietic lineages and the mRNA levels increase with the terminal differentiation of hemopoietic cells into granulocytes.