Pre-B-Lymphocyte Gene 1 (VPREB1)

CD179a (VpreB) is a 126 aa-long polypeptide with apparent MW of 16-18 kDa. It is expressed selectively at the early stages of B cell development, namely, in proB and early preB cells. CD179a has an Ig V domain-like structure, but lacks the last beta-strand (beta7) of a typical V domain. Instead, it has a carboxyl terminal end that shows no sequence homologies to any other proteins.

CD179a associates non-covalently with CD179b (lambda5 or lambda-like) carrying an Ig C domain-like structure to form an Ig light chain-like structure, which is called the surrogate light chain or pseudo light chain. In this complex, the incomplete V domain of CD179a appears to be complemented by the extra beta7 strand of CD179b.