THE SURROGATE LIGHT CHAIN IN B-CELL DEVELOPMENT

The proteins encoded by the V(preB) and lambda5 genes associate with each other to form a light (L) chain-like structure, the surrogate L chain. It can form Ig-like complexes with three partners - the classical heavy (H) chain, the D(H)J(H)C(mu)-protein, or the newly discovered p55 chain; these are expressed on the surface of pre-B cells at different stages of development. Here, Fritz Melchers and colleagues review the structures of the V(preB) and lambda5 genes in mouse and their relatives in humans, describe their pattern of expression, and speculate on their possible evolution and functions.