A novel gene product associated with mu chains in immature B cells.

A previously unreported B cell specific gene, which we have named 8HS-20, was isolated from the cDNA library of a pre-B cell clone by subtraction and differential hybridization. This gene is selectively expressed as a 0.75 kb transcript in pre-B and bone marrow-derived B cell lines; a transcript of the same size is also found in bone marrow and, albeit at low levels, in spleen. The deduced amino acid sequence of the 8HS-20 cDNA displayed homology to a B cell specific gene, VpreB-1, and to members of the immunoglobulin supergene family including V lambda, V kappa, VH, TCRV alpha, V beta and CD8. Biochemical analysis using purified antiserum against 8HS-20 oligopeptides indicates that the gene encodes proteins with mol. wts of 13.5, 14, 15.5 and 16 kDa, which associate with mu chains in pre-B cell lines, and that these molecules are expressed concomitantly with VpreB-1 and lambda 5 gene products in the same cell lines.