Lukusa T, Meulepas E, Fryns J P, Van den Berghe H, Cassiman J J
Center for Human Genetics, Onderwijs en Navorsing, Leuven, Belgium.
Cancer Genet Cytogenet. 1990 Oct 1;49(1):87-94. doi: 10.1016/0165-4608(90)90167-9.
The present study was performed to determine if the fra(X)(q27.3) site is inherently a high sister chromatid exchange (SCE) site independent of fragility. Therefore, we studied baseline and ethyl methane sulfonate (EMS)-induced SCEs in peripheral blood lymphocytes from 10 retarded fragile-X male patients and eight retarded nonfragile-X male controls. The distributions of SCE scores per chromosome within each experimental condition showed significant interindividual variability in response to EMS treatment in the fragile-X group. Each fragile-X patient was therefore compared with a matched control. No significant differences were found in the distribution of SCE scores per chromosome. In addition, at the Xq27 site, whatever the degree of expressed fragility, no significant differences between fragile-X and control groups were evident in the spontaneous or EMS-induced SCEs. The fra(X)(q27.3) site therefore is not a hot spot for spontaneous or EMS-induced SCEs. Because fluorodeoxyuridine (FUdR) treatment has been shown to induce SCE at this site, our results indicate that the Xq27.3 site must be structurally different from other nonfragile SCE sites.
本研究旨在确定脆性X综合征（fra(X)(q27.3)）位点是否本质上就是一个与脆性无关的高姐妹染色单体交换（SCE）位点。因此，我们研究了10名患有脆性X综合征的智力发育迟缓男性患者和8名非脆性X综合征的智力发育迟缓男性对照外周血淋巴细胞的基线及经甲基磺酸乙酯（EMS）诱导后的SCE情况。在每个实验条件下，每条染色体的SCE分数分布显示，脆性X综合征组在接受EMS处理后的个体间反应存在显著差异。因此，我们将每位脆性X综合征患者与其匹配的对照进行了比较。每条染色体的SCE分数分布未发现显著差异。此外，在Xq27位点，无论脆性表达程度如何，脆性X综合征组与对照组在自发或EMS诱导的SCE方面均无明显差异。因此，fra(X)(q27.3)位点并非自发或EMS诱导SCE的热点区域。由于已证明氟脱氧尿苷（FUdR）处理可在此位点诱导SCE，我们的结果表明，Xq27.3位点在结构上必定与其他非脆性SCE位点不同。
