Restriction fragment length polymorphism of the murine C4 and Slp genes: two C4 groups
Miller, R.D.; Aizawa, Y.; Shreffler, D.C.
Journal of Immunology 149(9): 2926-2934
1992
ISSN/ISBN: 0022-1767 PMID: 1357031 Document Number: 395765
We have examined the related H-2 genes coding for the fourth component of complement (C4) and the sex-limited protein (Slp) from 30 inbred mouse strains by Southern blot analysis. With four restriction enzymes, 11 RFLP patterns distributed among 26 different H-2 haplotypes have been identified. Strains of the same serologic H-2 haplotype were found to have identical RFLP patterns. It was confirmed that the number of C4-related genes in most haplotypes is two, Slp and C4; but H-2S-w16 (S-w16) and S-w19, which have the same RFLP pattern, have four and S-w7 has five. Although C4 and Slp have many similarities, they also were found to contain distinctive features: relative to Slp, each C4 allele examined has two insertions totalling 1.1 kb located in introns 14 and 15; and each Slp allele examined, excluding hybrids, has a provirus insertion upstream. No other large deletions or insertions were detected. The RFLP patterns are also due to 10 polymorphic restriction sites, which have been placed on standard maps; two are associated with Slp and eight are associated with C4.S-k strains, the only strains that express low serum levels of C4, have the same RFLP phenotype as S-w14, S-w18, and S-wx; S-k may have arisen from a recent common ancestor of these strains. Homologous recombination has been important in the formation of existing C4 alleles. However, based on complete linkage disequilibrium between three RFLP internal to C4, the haplotypes have been divided into two groups that may have functional significance.