DNA structural analysis of the Qa region in two BALB/c mouse substrains with different Qa-2 phenotypes reveals that a deletion of DNA has occurred in BALB/cBy (Qa2-) mice relative to BALB/c (Qa2+) mice. We propose that this deletion arises from unequal crossing-over and recombination between adjacent BALB/c class I genes and results in the generation of a hybrid class I gene in BALB/cBy mice. Furthermore, we suggest that this is a direct cause of the change in Qa-2 phenotype. Further support for this model was obtained from transfection experiments in which cloned genes from the equivalent part of the Qa region inC57BL/10 mice were introduced into L cells. Four C57BL/10 genes, arranged in two almost identical pairs, encode polypeptides that are precipitated from lysates of transfectants with anti-Qa-2/3 antiserum. Although loss of one pair of these genes in BALB/c mice has no qualitative effect on Qa-2 phenotype, the loss of both pairs of genes via gene fusion leads to the loss of the Qa- 2+ phenotype in BALB/cBy mice.
|Number of pages
|Proceedings of the National Academy of Sciences of the United States of America
|Published - 1985
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