Chromosome healing in mouse embryonic stem cells.
Chromosome healing in mouse embryonic stem cells.
复制标题
小鼠胚胎干细胞中的染色体愈合。
DOI：
10.1073/pnas.96.12.6781
复制
发表时间：
1999
影响因子：
11.1
通讯作者：
Murnane,JP
中科院分区：
文献类型：
--
作者：
Sprung,CN;Reynolds,GE;Jasin,M;Murnane,JP
The addition of new telomeres to the ends of broken chromosomes, termed chromosome healing, has been extensively studied in unicellular organisms; however, its role in the mammalian cell response to double-strand breaks is unknown. A system for analysis of chromosome healing, which involves the integration of plasmid sequences immediately adjacent to a telomere, has been established in mouse embryonic stem cells. This “marked” telomere contains aneogene for positive selection in G418, an I-SceI endonuclease recognition sequence for introducing double-strand breaks, and a herpes simplex virus thymidine kinase gene for negative selection with ganciclovir for cells that have lost the telomere. Transient expression of the I-SceI endonuclease results in terminal deletions involving telomeric repeat sequences added directly onto the end of the broken chromosome. The sites of addition of the new telomeres contain short regions of complementarity to telomeric repeat sequences. The most common site of addition is the last A of the ATAA 3′ overhang generated by the I-SceI endonuclease, without the loss of a single nucleotide from the end of the chromosome. The next most frequent site involved 5 bp of complementarity, which occurred after the loss of four nucleotides from the end of the chromosome. The new telomeres are generally much shorter than in the parental cell line, and most increase in size with time in culture. These results demonstrate that chromosome healing is a mechanism for repair of chromosome breaks in mammalian cells.
