The proteins encoded by the VpreB and lambda 5 pre-B cell-specific genes can associate with each other and with mu heavy chain.

Abstract

The murine pre-B cell-specific genes VpreB and .lambda.5, as well as the murine gene for .mu. heavy chain, were introduced into Ltk- fibroblast cells which normally do not express these genes. Stable transfectants carrying these genes produced the corresponding proteins of 15.5, 21.5, and 75 kD. They secreted the three proteins as a triple complex that could be immunnoprecipitated by .mu. heavy chain-specific antibodies, consisting of one VpreB, one .lambda.5, and one .mu. heavy chain. The .mu. heavy chain and .lambda.5 were disulfide-bonded with each other, while the VpreB protein was noncovalently associated. These experiments proved that the VpreB, .lambda.5 and .mu. H chain proteins can form a heavy/light chain-like heterocomplex.