Spontaneous amplification of interstitial telomeric bands in Chinese hamster ovary cells.
Spontaneous amplification of interstitial telomeric bands in Chinese hamster ovary cells.
复制标题
中国仓鼠卵巢细胞间质端粒带的自发扩增。
DOI：
10.1159/000133899
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
DeRubeis,D
中科院分区：
文献类型：
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作者：
Pandita,TK;DeRubeis,D
中国仓鼠细胞系已被广泛用于探索应激条件下基因扩增的机制。然而，由于技术原因，中国仓鼠细胞在非应激条件下的基因扩增研究受到限制。我们开始研究的放大机制，通过检查的频率间质端粒带（ITBs）在不断增长的文化，荧光原位杂交（FISH），使用（TTAGGG）n探针。我们发现其中一条染色体在中国仓鼠卵巢（CHO）细胞中唯一地表现出ITB扩增，但在耐药突变CHO细胞或中国仓鼠V79细胞中没有。DNA损伤剂或DNA合成抑制剂不能诱导ITBs扩增。为了研究介导ITB扩增的早期事件，我们开发了克隆，并确定了标记染色体上额外ITB的获得频率为10- 5至10- 3/细胞倍增。使用DNA链特异性FISH，我们发现扩增的初始事件之一是等染色体形成。我们的观察结果支持姐妹染色单体融合参与自发ITB扩增的启动。
Chinese hamster cell lines have been widely used to explore the mechanism of gene amplification under stress conditions. Investigations of gene amplification in Chinese hamster cells under nonstress conditions, however, have been limited due to technical reasons. We initiated studies on the amplification mechanism by examining the frequency of interstitial telomeric bands (ITBs) in continuously growing cultures by fluorescence in situ hybridization (FISH), using a (TTAGGG)n probe. We found that one of the chromosomes uniquely exhibit amplification of ITBs in Chinese hamster ovary (CHO) cells but not in drug-resistant mutant CHO cells or in Chinese hamster V79 cells. Amplification of ITBs could not be induced by DNA damaging agents or DNA synthesis inhibitors. To investigate the early events that mediate ITB amplification, we developed clones and determined that the frequency of acquisition of additional ITBs on the marker chromosome was in the range of 10–5to 10–3per cell doubling. Using DNA strand-specific FISH, we found that one of the initial events of amplification is isochromosome formation. Our observations support the involvement of sister chromatid fusion in the initiation of spontaneous ITB amplification.