Slijepcevic P, Xiao Y, Dominguez I, Natarajan A T
Department of Radiation Genetics and Chemical Mutagenesis, University of Leiden, Wassenaarseweg 72, NL-2300 RA Leiden, The Netherlands.
Chromosoma. 1996 Jun;104(8):596-604. doi: 10.1007/BF00352299.
The Chinese hamster genome contains a total of 18 cytologically detectable arrays of interstitial telomeric sequences. A combination of G-banding and two-colour fluorescence in situ hybridization revealed that 25 out of 27 (93%) breakpoints of spontaneously occurring terminal deletions in four immortalized Chinese hamster cell lines were located in chromosomal regions containing interstitial telomeric sequences. Each of the four immortalized Chinese hamster cell lines expressed telomerase. Radiation experiments revealed the sensitivity of interstitial telomeric sequences to radiation-induced chromosomal breakage in all telomerase-positive cell lines. However, radiation-induced chromosomal breakage at interstitial telomeric sites in non-transformed, primary Chinese hamster cells was almost non-existent. Telomerase activity in primary Chinese hamster cells was not detected. These results indirectly suggest that interstitial telomeric sites represent a favourable substrate for chromosomal healing.
中国仓鼠基因组总共包含18个可通过细胞学检测到的间质端粒序列阵列。G带分析和双色荧光原位杂交相结合的方法显示，在四种永生化中国仓鼠细胞系中，27个自发发生的末端缺失断点中有25个（93%）位于含有间质端粒序列的染色体区域。这四种永生化中国仓鼠细胞系均表达端粒酶。辐射实验表明，在所有端粒酶阳性细胞系中，间质端粒序列对辐射诱导的染色体断裂敏感。然而，在未转化的原代中国仓鼠细胞中，间质端粒位点几乎不存在辐射诱导的染色体断裂。未检测到原代中国仓鼠细胞中的端粒酶活性。这些结果间接表明，间质端粒位点是染色体修复的有利底物。
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