Institut J. Monod, Centre National de la Recherche Scientifique, Université Paris 7, Tour 43, 2 place Jussieu, 75251 Paris, Cedex 05, France.
Proc Natl Acad Sci U S A. 1985 Jan;82(2):503-5. doi: 10.1073/pnas.82.2.503.
Heteroduplexes with single base-pair mismatches of known sequence were prepared by annealing separated strands of bacteriophage lambda DNA and used to transfect Escherichia coli. Each of the eight possible single base-pair mismatches was constructed. Genetic analysis of the progeny phages obtained from transfected bacteria indicates that the E. coli mismatch repair system does not recognize (or does not repair) all single base-pair mismatches with equal efficiency. In particular, the A.G, C.T, and C.C mismatches appear to be less repaired than any others. The mutator character of mismatch repair-deficient mutants suggests that such unrepaired mismatches should occur infrequently during E. coli DNA replication.
已知序列的单碱基对错配异源双链体通过使噬菌体 λ DNA 的分离链退火制备,并用于转染大肠杆菌。构建了所有八种可能的单碱基对错配。从转染细菌获得的子代噬菌体的遗传分析表明,大肠杆菌错配修复系统不能以相同的效率识别(或修复)所有单碱基对错配。特别是,A.G、C.T 和 C.C 错配似乎比其他错配修复得更少。错配修复缺陷突变体的突变特征表明,在大肠杆菌 DNA 复制过程中,这种未修复的错配应该很少发生。