TY - JOUR
T1 - Mismatch repair protein hMSH2-hMSH6 recognizes mismatches and forms sliding clamps within a D-loop recombination intermediate
AU - Honda, Masayoshi
AU - Okuno, Yusuke
AU - Hengel, Sarah R.
AU - Martín-López, Juana V.
AU - Cook, Christopher P.
AU - Amunugama, Ravindra
AU - Soukup, Randal J.
AU - Subramanyam, Shyamal
AU - Fishel, Richard
AU - Spies, Maria
PY - 2014/1/21
Y1 - 2014/1/21
N2 - High fidelity homologous DNA recombination depends on mismatch repair (MMR), which antagonizes recombination between divergent sequences by rejecting heteroduplex DNA containing excessive nucleotide mismatches. The hMSH2-hMSH6 heterodimer is the first responder in postreplicative MMR and also plays a prominent role in heteroduplex rejection. Whether a similar molecular mechanism underlies its function in these two processes remains enigmatic. We have determined that hMSH2-hMSH6 efficiently recognizes mismatches within a D-loop recombination initiation intermediate. Mismatch recognition by hMSH2-hMSH6 is not abrogated by human replication protein A (HsRPA) bound to the displaced single-stranded DNA (ssDNA) or by HsRAD51. In addition, ATP-bound hMSH2-hMSH6 sliding clamps that are essential for downstream MMR processes are formed and constrained within the heteroduplex region of the D-loop. Moreover, the hMSH2-hMSH6 sliding clamps are stabilized on the D-loop by HsRPA bound to the displaced ssDNA. Our findings reveal similarities and differences in hMSH2-hMSH6 mismatch recognition and sliding-clamp formation between a D-loop recombination intermediate and linear duplex DNA.
AB - High fidelity homologous DNA recombination depends on mismatch repair (MMR), which antagonizes recombination between divergent sequences by rejecting heteroduplex DNA containing excessive nucleotide mismatches. The hMSH2-hMSH6 heterodimer is the first responder in postreplicative MMR and also plays a prominent role in heteroduplex rejection. Whether a similar molecular mechanism underlies its function in these two processes remains enigmatic. We have determined that hMSH2-hMSH6 efficiently recognizes mismatches within a D-loop recombination initiation intermediate. Mismatch recognition by hMSH2-hMSH6 is not abrogated by human replication protein A (HsRPA) bound to the displaced single-stranded DNA (ssDNA) or by HsRAD51. In addition, ATP-bound hMSH2-hMSH6 sliding clamps that are essential for downstream MMR processes are formed and constrained within the heteroduplex region of the D-loop. Moreover, the hMSH2-hMSH6 sliding clamps are stabilized on the D-loop by HsRPA bound to the displaced ssDNA. Our findings reveal similarities and differences in hMSH2-hMSH6 mismatch recognition and sliding-clamp formation between a D-loop recombination intermediate and linear duplex DNA.
KW - Homeologous recombination
KW - Homologous recombination
KW - Mismatch dna repair
KW - Single-molecule
KW - Total internal reflection fluorescence microscopy
UR - https://www.scopus.com/pages/publications/84892931767
U2 - 10.1073/pnas.1312988111
DO - 10.1073/pnas.1312988111
M3 - Article
C2 - 24395779
AN - SCOPUS:84892931767
SN - 0027-8424
VL - 111
SP - E316-E325
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 3
ER -