TY - JOUR
T1 - Methyl-directed repair of frameshift heteroduplexes in cell extracts from Escherichia coli
AU - Learn, B. A.
AU - Grafstrom, R. H.
PY - 1989
Y1 - 1989
N2 - The methyl-directed DNA repair efficiency of a series of M13mp9 frameshift heteroduplexes containing 1, 2, or 3 unpaired bases was determined by using an in vitro DNA mismatch repair assay. Repair of hemimethylated frameshift heteroduplexes in vitro was directed to the unmethylated strand; was dependent on MutH, MutL, and MutS; and was equally efficient on base insertions and deletions. However, fully methylated frameshift heteroduplexes were resistant to repair, while totally unmethylated substrates were repaired with no strand bias. Hemimethylated 1-, 2-, or 3-base insertion and deletion heteroduplexes were repaired by the methyl-directed mismatch repair pathway as efficiently as the G · T mismatch. These results are consistent with earlier in vivo studies and demonstrate the involvement of methyl-directed DNA repair in the efficient prevention of frameshift mutations.
AB - The methyl-directed DNA repair efficiency of a series of M13mp9 frameshift heteroduplexes containing 1, 2, or 3 unpaired bases was determined by using an in vitro DNA mismatch repair assay. Repair of hemimethylated frameshift heteroduplexes in vitro was directed to the unmethylated strand; was dependent on MutH, MutL, and MutS; and was equally efficient on base insertions and deletions. However, fully methylated frameshift heteroduplexes were resistant to repair, while totally unmethylated substrates were repaired with no strand bias. Hemimethylated 1-, 2-, or 3-base insertion and deletion heteroduplexes were repaired by the methyl-directed mismatch repair pathway as efficiently as the G · T mismatch. These results are consistent with earlier in vivo studies and demonstrate the involvement of methyl-directed DNA repair in the efficient prevention of frameshift mutations.
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U2 - 10.1128/jb.171.12.6473-6481.1989
DO - 10.1128/jb.171.12.6473-6481.1989
M3 - Article
C2 - 2687237
AN - SCOPUS:0024358059
VL - 171
SP - 6473
EP - 6481
JO - Journal of Bacteriology
JF - Journal of Bacteriology
SN - 0021-9193
IS - 12
ER -