Somatic hypermutation in MutS homologue (MSH)3-, MSH6-, and MSH3/MSH6-deficient mice reveals a role for the MSH2-MSH6 heterodimer in modulating the base substitution pattern
M. Wiesendanger et al., Somatic hypermutation in MutS homologue (MSH)3-, MSH6-, and MSH3/MSH6-deficient mice reveals a role for the MSH2-MSH6 heterodimer in modulating the base substitution pattern, J EXP MED, 191(3), 2000, pp. 579-584
Although the primary function of the DNA mismatch repair (MMR) system is to
identify and correct base mismatches that have been erroneously introduced
during DNA replication, recent studies have further implicated several MMR
components in somatic hypermutation of immunoglobulin (Ig) genes. We studi
ed the immune response in mice deficient in MutS homologue (MSH)3 and MSH6,
two mutually exclusive partners of MSH2 that have not been examined previo
usly for their role in Ig hypermutation. In Msh6(-/-) and Msh3(-/-)/Msh6(-/
-) mice, base substitutions are preferentially targeted to G and C nucleoti
des and to an RGYW hot spot, as has been shown previously in Msh2(-/-) mice
. In contrast, Msh3(-/-) mice show no differences from their littermate con
trols. These findings indicate that the MSH2-MSH6 heterodimer, but not the
MSH2-MSH3 complex, is responsible for modulating Ig hypermutation.