Wasylyk B, Chambon P
Eur J Biochem. 1979 Aug 1;98(2):317-27. doi: 10.1111/j.1432-1033.1979.tb13191.x.
Chromatin was assembled in vitro from simian virus 40 DNA form I and the calf-thymus four histones H2A, H2B, H3 and H4. Transcription with calf thymus RNA polymerases A and B (I and II) was greatly inhibited. Nucleosomes were found to inhibit both RNA chain initiation and elongation. The inhibition of elongation could be relieved by increasing ionic strength, suggesting that electrostatic interactions between histone octamer and DNA have to be broken for RNA polymerase to transcribe DNA organised into nucleosomes.
染色质是在体外由猴病毒40 DNA I型和小牛胸腺的四种组蛋白H2A、H2B、H3和H4组装而成。小牛胸腺RNA聚合酶A和B（I和II）的转录受到极大抑制。发现核小体同时抑制RNA链的起始和延伸。增加离子强度可以解除对延伸的抑制，这表明为了使RNA聚合酶转录组装成核小体的DNA，组蛋白八聚体与DNA之间的静电相互作用必须被打破。
