Hirsch B
Department of Laboratory Medicine and Pathology, University of Minnesota Hospital and Clinics, Minneapolis 55455.
Hum Genet. 1991 Jul;87(3):302-6. doi: 10.1007/BF00200908.
To investigate the relationship between common fragile sites and sister chromatid exchange (SCE), lymphocyte cultures were treated with aphidicolin and bromodeoxyuridine (BrdU) and analyzed using a sequential G----SCE staining protocol. A total of 1,163 SCEs were mapped to their corresponding G-band sites, which were assigned to one of the following four categories: fragile sites expressed; fragile sites nonexpressed; nonfragile sites with breaks; or nonfragile sites with no breaks. The designated common fragile sites were found to be preferred locations for SCE formation, not only when these sites were "expressed" as visible gaps or breaks, but even when they were "nonexpressed" in the cell. SCEs were also more likely to occur at nonfragile sites with breaks than at nonfragile with no break sites. Further, SCEs were found to be distributed nonrandomly across fragile sites and nonfragile sites, and among the fragile sites, the high frequency SCE sites were highly correlated with the high frequency breakage sites. These data support the hypothesis of common steps in the mechanism of aphidicolin-induced SCE formation and common fragile site expression.
为了研究常见脆性位点与姐妹染色单体交换（SCE）之间的关系，采用阿非科林和溴脱氧尿苷（BrdU）处理淋巴细胞培养物，并使用连续的G-SCE染色方案进行分析。总共1163个SCE被定位到其相应的G带位点，这些位点被归为以下四类之一：表达的脆性位点；未表达的脆性位点；有断裂的非脆性位点；或无断裂的非脆性位点。结果发现，指定的常见脆性位点不仅在这些位点表现为可见的间隙或断裂（即“表达”）时，而且在细胞中“未表达”时，都是SCE形成的首选位置。SCE在有断裂的非脆性位点比在无断裂的非脆性位点更易发生。此外，发现SCE在脆性位点和非脆性位点之间呈非随机分布，并且在脆性位点中，高频SCE位点与高频断裂位点高度相关。这些数据支持了阿非科林诱导SCE形成机制和常见脆性位点表达存在共同步骤的假说。
