Dual gene control for erythrocyte antigen H-2.7 (G) : a determinant on complement component C4d
David, C.S.; Savarirayan, S.S.
Transplantation Proceedings 13(1 Pt 2): 969-972
1981
ISSN/ISBN: 0041-1345 PMID: 6168077 Document Number: 180306
An H-2 variant arising from an intracistronic chromosomal exchange within C4 genes is described. The variant chromosome expresses normal H-2b alleles at the K, I and D regions. It is proposed that the C4 genes comprise beta 1 and alpha 2 genes from the Sb parent and the gamma 1 gene from the Sf parent. This variant chromosome, when heterozygous with the H-2k chromosome ( beta 2, alpha 1, gamma 2), can express the C4d fragment determinant H-2.7 (by trans-gene complementation [ alpha 1, gamma 1]) on the erythrocyte membrane as well as synthesising normal levels of C4. These results suggest that C4 deficiency in mice may be caused by juxtaposition of incompatible genes coding for the alpha and the gamma chains of C4 on the same chromosome by intracistronic chromatid exchange, rather than by a defect in the structural gene controlling synthesis of C4.