组蛋白与hAMFR基因启动子的结合对体外转录活性的影响

Effects of the Interaction between Histone and hAMFR Gene Promoter on the Transcription Activity in vitro

采用从鸡血红细胞中分离纯化的组蛋白、从HeLa细胞核中革取的含有RNA聚合酶Ⅱ和多种Ⅱ类基因转录因子的可溶性抽提物，以及从非洲爪蟾卵细胞核中提取的革取物热处理物上清（HTS）用于核小体构建，以含有人自班移动因子受体（hAMFR）基因启动子序列的DNA片段为模板进行体外转录实验，结果表明，组蛋白和转录因子在hAMFR基因启动子序列上的竞争性结合对转录活性具有重要的影响作用，在启动子区域预先构建的核小体能够抑制转录活性；反之在启动于上先形成转录起始复合物则能防止核小体的转录抑制作用；当组蛋白和转录因子同时作用在DNA模板时，转录活性取决于组蛋白和转录因子的相对浓度。

The effects of interaction between histones and human autocrine motility factorreceptor (hAMFR gene promoter on the transcription activity in vitro was investigatedby using histones purified from chicken erythrocytes, HeLa cell nuclear extracts andheat-treated supematants of Xenopus eggs. The results showed that the competitivebinding of histones and transcription factors at the promoter of hAMFR gene was veryimportant to the transcription in vitro. If a pre-inihation complex was formed withHeLa cell nuclear extracts on the promoter prior to nucleosome assembly, it wouldprevent nucleosome-mediated transcription repression. When the nucleosome wasassembled on the promoter in advance, the transcription activity could be repressed.When histones and HeLa cell nuclear extracts were mixed in the reactionsimultaneously, the transcriphon activity would depend on the relative amount ofhistones to that of HeLa cell nuclear extracts.