The products of Pre-B cell-specific genes (λ5 and VPreB) and the immunoglobulin μ chain form a complex that is transported onto the cell surface

Abstract

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.