DNA loop repair by human cell extracts.
An activity in human cell extracts is described that repairs DNA with loops of five or more unpaired bases. Repair is strand-specific and is directed by a nick located 5' or 3' to the loop. This repair is observed in a colorectal cancer cell line that is devoid of a wild-type hMLH1 gene and is deficient in repair of mismatches. However, a cell line with deletions in both hMSH2 alleles is deficient in repair of both loops and mismatches. Defects in loop repair may be relevant to the repetitive-sequence instability observed in cancers and other hereditary diseases.
Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709.
A
A
Umar
J C
JC
Boyer
T A
TA
Kunkel
D048868:Adaptor Proteins, Signal Transducing; D001482:Base Composition; D001483:Base Sequence; D002352:Carrier Proteins; D002457:Cell Extracts; D002460:Cell Line; D015179:Colorectal Neoplasms / Q000235:genetics*; D004260:DNA Repair; D004276:DNA, Satellite / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D009363:Neoplasm Proteins / Q000235:genetics* / Q000502:physiology; D009687:Nuclear Proteins; D009692:Nucleic Acid Heteroduplexes / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000502:physiology; D012091:Repetitive Sequences, Nucleic Acid; D014407:Tumor Cells, Cultured
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D002457:Cell Extracts; D004276:DNA, Satellite; D004268:DNA-Binding Proteins; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D009692:Nucleic Acid Heteroduplexes; D011518:Proto-Oncogene Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein