Abrams J M, Schimke R T
Department of Biological Sciences, Stanford University, CA 94305.
Proc Natl Acad Sci U S A. 1989 Dec;86(23):9380-4. doi: 10.1073/pnas.86.23.9380.
The bacterial xanthine-guanine phosphoribosyltransferase (GPT) gene was fused to a metal-responsive promoter and transfected into a murine cell line. Clonal transformants harboring metal-responsive or nonresponsive GPT genes (using a thymidine kinase promoter) were then studied for the loss of transfected gene function either during periods of constitutive expression or during periods of induced activity. Nontoxic levels of cadmium and zinc markedly reduced the frequency of mutagenesis in all transfected lines irrespective of transcriptional status. A survey of 17 GPT-clones derived from two original transfectants showed partial or complete excisions of the transfected gene in every case. These studies show that quantities of cadmium and zinc that induce metallothioneins also suppress the incidence of deletions in murine cells.
将细菌黄嘌呤 - 鸟嘌呤磷酸核糖转移酶（GPT）基因与金属反应性启动子融合，并转染到小鼠细胞系中。然后研究携带金属反应性或无反应性GPT基因（使用胸苷激酶启动子）的克隆转化体在组成型表达期或诱导活性期转染基因功能的丧失情况。镉和锌的无毒水平显著降低了所有转染细胞系中的诱变频率，而与转录状态无关。对来自两个原始转染体的17个GPT克隆的调查显示，在每种情况下转染基因都有部分或完全切除。这些研究表明，诱导金属硫蛋白的镉和锌量也会抑制小鼠细胞中缺失的发生率。
