Ayares D, Ganea D, Chekuri L, Campbell C R, Kucherlapati R
Mol Cell Biol. 1987 May;7(5):1656-62. doi: 10.1128/mcb.7.5.1656-1662.1987.
We studied the ability of mammalian cells to repair single-stranded nicks, gaps, and loops in DNA duplexes. Heteroduplexes prepared from derivatives of the shuttle vector pSV2neo were introduced into monkey COS cells. After replication, the plasmids were recovered and used to transform Escherichia coli. Plasmid DNA from the recovered colonies was tested for repair at each of six different sites. We observed that mammalian cells are capable of repairing single-stranded gaps and free single-stranded ends most efficiently. Regions containing twin loops were recognized, and one of the loops was excised. Portions of the molecules containing small single loops were also repaired. Markers which were 58 nucleotides apart were corepaired with nearly 100% efficiency, while markers which were 1,000 nucleotides or more apart were never corepaired. The mechanisms involved in heteroduplex repair in mammalian cells seem to be similar to those involved in repairing DNA lesions caused by physical and chemical agents.
我们研究了哺乳动物细胞修复DNA双链中单链切口、缺口和环的能力。将穿梭载体pSV2neo衍生物制备的异源双链体导入猴COS细胞。复制后，回收质粒并用于转化大肠杆菌。对回收菌落的质粒DNA在六个不同位点的每一个进行修复检测。我们观察到，哺乳动物细胞能够最有效地修复单链缺口和游离单链末端。含有双环的区域被识别，其中一个环被切除。含有小单环的分子部分也得到了修复。相距58个核苷酸的标记物共修复效率接近100%，而相距1000个核苷酸或更多的标记物从未共修复。哺乳动物细胞中异源双链体修复所涉及的机制似乎与修复物理和化学试剂引起的DNA损伤所涉及的机制相似。
