RNA聚合酶结合位点在分级分离染色质中的分布
Distribution of RNA polymerase binding sites in fractionated chromatin.
作者信息
Simpson R T
出版信息
Proc Natl Acad Sci U S A. 1974 Jul;71(7):2740-3. doi: 10.1073/pnas.71.7.2740.
Calf-thymus chromatin was fractionated by ion-exchange chromatography on ECTHAM-cellulose and sucrose gradient sedimentation. [ECTHAM-cellulose is a cationic adsorbent prepared by coupling tris(hydroxymethyl)aminomethane to cellulose with epichlorohydrin.] The capacity of these fractionated chromatins to support RNA synthesis by DNA-dependent RNA polymerase of Escherichia coli was examined, using procedures that permit measurement of binding site frequency. Unfractionated calf thymus chromatin has 5-10% as many binding sites as protein-free DNA. By combination of the two fractionation methods, chromatin samples were obtained containing as few as 2% and as many as 47% of the number of binding sites found on protein-free DNA.
小牛胸腺染色质通过在ECTHAM-纤维素上进行离子交换色谱和蔗糖梯度沉降进行分级分离。[ECTHAM-纤维素是一种阳离子吸附剂，通过用环氧氯丙烷将三（羟甲基）氨基甲烷偶联到纤维素上制备而成。] 使用允许测量结合位点频率的方法，检测了这些分级分离的染色质支持大肠杆菌依赖DNA的RNA聚合酶进行RNA合成的能力。未分级分离的小牛胸腺染色质的结合位点数量是无蛋白质DNA的5%-10%。通过将两种分级分离方法相结合，获得了染色质样品，其结合位点数量少至无蛋白质DNA上发现的结合位点数量的2%，多至47%。
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