Molecular genetics of the K end of the murine MHC.

A systematic search of cloned DNA from the region between the Pb (A beta 3) and Ob (A beta 2) genes of the murine major histocompatibility complex (MHC) has revealed the presence of at least seven new genes. Three of these genes show significant similarity to MHC class II antigens. Two of the other genes are members of a superfamily of transport protein genes and are believed to function in the transport of antigenic peptides during antigen processing. Genes encoding at least two subunits of a large intracellular protein complex (the LMP complex) that is believed to be involved in antigen processing were previously mapped to the same genetic region. This data suggests that this region of the MHC contains, in addition to MHC class I and class II genes whose products provide the scaffolding for antigen presentation, a cluster of genes required for antigen processing.