Journal of Nucleic Acids

Review Article

DNA Mismatch Repair in Eukaryotes and Bacteria

Table 1

Distribution of MMR proteins.
Molecular functionThermus thermophilusEscherichia coliSaccharomyces cerevisiaeHomo sapiens
Mismatch recognitionMutSMutS M u t S 𝛼 (MSH2/MSH6) MutS 𝛽 (MSH2/MSH3) M u t S 𝛼 (MSH2/MSH6) MutS 𝛽 (MSH2/MSH3)
Strand incision 𝛽 - c l a m p ∗ 1 —PCNAPCNA
clamp- l o a d e r ∗ 1 RFCRFC
MutL M u t L 𝛼 (MLH1/PMS1) M u t L 𝛾 ∗ 2 (MLH1/MLH3) M u t L 𝛼 (MLH1/PMS2) M u t L 𝛾 ∗ 2 (MLH1/MLH3)
Strand incision—MutH——
Match makingMutLMutL M u t L 𝛼 (MLH1/PMS1) MutL 𝛽 (MLH1/MLH2) MutL 𝛾 (MLH1/MLH3) M u t L 𝛼 (MLH1/PMS2) MutL 𝛽 (MLH1/PMS1) MutL 𝛾 (MLH1/MLH3)
Strand excision (single-stranded DNA-binding)SSBSSBRPARPA
Strand excision (exonuclease) RecJ
ExoI
RecJ
ExoI
ExoVII
ExoX		 E X O 1 ∗ 3 E X O 1 ∗ 3
Strand excision (helicase)UvrD
UvrD
——
Repair synthesisDNA polymerase IIIDNA polymerase IIIDNA polymerase 𝛿 DNA polymerase 𝛿
∗ 1 The involvement of bacterial clamp and clamp-loader in the strand incision reaction has not yet been confirmed. ∗ 2 It is demonstrated that the endonuclease motif in MLH3 is responsible for in vivo MMR [83]; however, the endonuclease activity of MutL 𝛾 has not yet been confirmed biochemically. ∗ 3 In yeast and human, EXO1 has the 5 -flap endonuclease activity in addition to 5 - 3 exonuclease activity.