Identification of H-2-controlled structural variants of the murine Slp protein and demonstration of cis-regulation of its expression.

H-2 haplotype-related structural variation in Slp beta-chains was detected by the limited proteolysis peptide mapping technique. Two distinct peptide patterns were distinguished: Slp.1 was found in strains carrying the S regions of the H-2d and H-2s haplotypes, and Slp.2 was found in strains bearing the S region of H-2w7. These different patterns were expressed codominantly in male (Sd X Sw7)F1 hybrids, whereas only the Slp.2 pattern was expressed in female heterozygotes. The 2 beta-chains are most likely the products of alleles of the Slp structural gene, which must then be located in the murine major histocompatibility complex, very probably in the S region.