STRAND-SPECIFIC MISMATCH CORRECTION IN NUCLEAR EXTRACTS OF HUMAN AND DROSOPHILA-MELANOGASTER CELL-LINES
STRAND-SPECIFIC MISMATCH CORRECTION IN NUCLEAR EXTRACTS OF HUMAN AND DROSOPHILA-MELANOGASTER CELL-LINES
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DOI：
10.1073/pnas.87.15.5837
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发表时间：
1990-08-01
影响因子：
11.1
通讯作者：
MODRICH, P
中科院分区：
文献类型：
--
作者：
HOLMES, J;CLARK, S;MODRICH, P
Nuclear extracts derived from HeLa and Drosophila melanogster KC cell lines have been found to correct single base-base mispairs within open circular DNA heteroduplexes containing a strand-specific, site-specific incision location 808 base pairs from the mismatch. Correction in both extract systems is strand specific, being highly biased to the incised DNA strand. Different mispairs within a homologous set of heteroduplexes were processed with different efficiencies (G.cntdot.T > G.cntdot.G .simeq. A.cntdot.C > C.cntdot.C), and correction was accompanied by mismatch-dependent DNA synthesis localized to the region spanning the mispair and the strand break, thus demonstrating that mismatch recognition is associated with the repair reaction. Correction of each of these heteroduplexes was abolished by aphidicolin but was relatively insensitive to the presence of high concentrations of ddTTP, indicating probable involvement and .alpha. and/or .delta. class DNA polymerase(s). These findings suggest that higher eukaryotic cells possess a general, strand-specific mismatch repair system analogous to the Escherichia coli mutHLS and the Streptococcus pneumoniae hexAB pathways, systems that contribute in the major way to the genetic stability of these bacterial species.
