THE PRODUCTS OF PRE-B-CELL-SPECIFIC GENES (LAMBDA-5 AND VPREB) AND THE IMMUNOGLOBULIN MU-CHAIN FORM A COMPLEX THAT IS TRANSPORTED ONTO THE CELL-SURFACE

We constructed expression vectors coding for the two pre-B-specific genes, VpreB and λ5, and transfected them together with a µ vector (µtm) into Ig−, myeloma cells. In a transfectant expressing all three introduced genes, the µtm chain is transported on the cell surface. A biochemical analysis demonstrated that, in these cells, the µtm chain is associated noncovalently with an 18-kD protein and covalently with a 22-kD protein, which are most likely the products of VpreB and λ5, respectively. Our results, thus, strongly suggest that the products of λ5 and VpreB bind to µ chains and have the same capacity as conventional Ig L chains to allow surface expression of µ chains. © 1990, Rockefeller University Press., All rights reserved.