Jordano J, Perucho M
Nucleic Acids Res. 1986 Sep 25;14(18):7361-78. doi: 10.1093/nar/14.18.7361.
The chromatin structure of the human c-K-ras gene has been investigated in various cultured normal and tumor human cells and in a rat cell line transformed with the human oncogene. The promoter region is hypersensitive to DNAse I, micrococcal nuclease, endogenous nucleases and to S1 nuclease in supercoiled plasmids. This hypersensitive region is present in the different cell types analyzed and both normal and mutant alleles exhibit similar general sensitivity to DNAse I digestion in the same tumor cells. However, the 5' more distal DNAse I hypersensitive site, which is coincident with a region of the gene containing sequence homologies with known enhancers, exhibits variable sensitivity which appears to be higher in the tumor than in the normal and in the human than in the rat cells which we have analyzed. These data suggest the presence of specific factors interacting with the promoter sequences and delimits the transcription unit of the c-K-ras locus.
已在多种培养的正常和肿瘤人类细胞以及用人癌基因转化的大鼠细胞系中研究了人类c-K-ras基因的染色质结构。启动子区域对DNA酶I、微球菌核酸酶、内源性核酸酶以及超螺旋质粒中的S1核酸酶高度敏感。在分析的不同细胞类型中均存在这种高敏区域，并且在同一肿瘤细胞中，正常和突变等位基因对DNA酶I消化表现出相似的总体敏感性。然而，5'端更远的DNA酶I高敏位点与该基因中一个与已知增强子具有序列同源性的区域重合，其敏感性可变，在肿瘤细胞中似乎高于正常细胞，在人类细胞中高于我们所分析的大鼠细胞。这些数据表明存在与启动子序列相互作用的特定因子，并界定了c-K-ras基因座的转录单元。
