DESCRIPTION: This small, short term research project aims to identify and characterize new genes exhibiting sequence identity with variable region genes belonging to the immunoglobulin/T cell antigen receptor/CD8 subfamily of the immunoglobulin gene superfamily. The study design is based on the observation that two short portions of the V region of immunoglobulin light chains and T cell receptors are highly conserved in all vertebrates. These conserved regions consist of three to four amino acids that are located about 63 amino acids (190 base pairs) apart. The applicants will use short, low-degeneracy oligos and primers for isolating homologous gene segments from human genomic DNA. Novel gene segments will be used to isolate full length cDNAs or genes from libraries. Novel genes will be subcloned into expression vectors, and fusion proteins will be isolated to produce monoclonal antibodies. These antibodies will be used to examine tissue-specific expression of the genes and to further characterize the protein products. The ultimate objective is to identify new genes encoding variable region-related molecules that are functional determinants in the immune system.