10.1371/journal.pone.0011182.g005 Sergio Roa Sergio Roa Ziqiang Li Ziqiang Li Jonathan U. Peled Jonathan U. Peled Chunfang Zhao Chunfang Zhao Winfried Edelmann Winfried Edelmann Matthew D. Scharff Matthew D. Scharff Model for MMR resolution of AID-generated dU:G mispairs. Public Library of Science 2010 mmr aid-generated 2010-06-17 01:34:49 Figure https://plos.figshare.com/articles/figure/_Model_for_MMR_resolution_of_AID_generated_dU_G_mispairs_/515689 <p>In the DNA deamination model, MSH2/MSH6 recognizes the initial AID-generated dU:G lesion, the damaged strand is excised by Exo1, and Polη is preferentially recruited to the nontranscribed strand (NTS) to generate mutations at A sites within W<u>A</u> motifs. Fewer T sites within <u>T</u>W motifs are mutated, contributing to the singular A≫T and W<u>A</u>≫<u>T</u>W biases that characterize SHM and reflect the reduced targeting of A sites by Polη in the transcribed strand (TS). We highlight here the error-free repair effect of MMR at the dU:G mispairs within the excised patch, which is revealed in <i>Msh2<sup>−/−</sup>Msh6<sup>−/−</sup></i> mice by a significant increase in unrepaired dU:G lesions that are replicated as transitions at C:G sites in WR<u>C</u>/<u>G</u>YW hotspots (i.e. C-to-T within WR<u>C</u> in the NTS, and G-to-A within <u>G</u>YW as a reflection of C-to-T mutations in the TS).</p>