Abruzzo M A, Pettay D, Mayer M, Jacobs P A
Hum Genet. 1986 May;73(1):20-2. doi: 10.1007/BF00292657.
Caffeine has been reported to enhance the expression of the fragile X [fra(X)] and common fragile sites in peripheral blood lymphocyte cultures (PBLC) treated with 5-fluorodeoxyuridine (FUdR). One of the effects of caffeine on replicating cells is inhibition of DNA repair suggesting that fragile sites may be regions of DNA with a high rate of misreplication under the conditions of thymidylate stress induced by FUdR. We have studied the effect of caffeine on the expression of the fra(X) and common folate-dependent fragile sites in PBLC from two fra(X) expressing individuals and in five lymphoblastoid cell lines (LCL) established from individuals in families in which the fra(X) is segregating. Caffeine did not enhance the expression of the fra(X) in the PBLC or in the three LCL from fra(X) expressing individuals nor did it elicit fra(X) expression in LCL from a non-expressing obligate-carrier female and a transmitting male. However, in all cultures there was a marked increase of common fragile site expression due to caffeine treatment. These data suggest that the mechanism of expression of the common fragile sites and the fra(X) may be quite different.
据报道，咖啡因可增强经5-氟脱氧尿苷（FUdR）处理的外周血淋巴细胞培养物（PBLC）中脆性X [fra(X)]和常见脆性位点的表达。咖啡因对复制细胞的作用之一是抑制DNA修复，这表明在FUdR诱导的胸苷酸应激条件下，脆性位点可能是错配率较高的DNA区域。我们研究了咖啡因对两名表达fra(X)个体的PBLC以及从fra(X)正在分离的家族中的个体建立的五个淋巴母细胞系（LCL）中fra(X)和常见叶酸依赖性脆性位点表达的影响。咖啡因并未增强表达fra(X)个体的PBLC或三个LCL中fra(X)的表达，也未在一名未表达的 obligate-carrier女性和一名传递男性的LCL中引发fra(X)表达。然而，在所有培养物中，由于咖啡因处理，常见脆性位点的表达均显著增加。这些数据表明，常见脆性位点和fra(X)的表达机制可能大不相同。
