Trends Biochem Sci. 2014 Dec;39(12):577-86. doi: 10.1016/j.tibs.2014.10.004.
The packaging of DNA into chromatin limits sequence accessibility, which affects all DNA-based processes including transcription. Indeed, the fundamental unit of chromatin, the nucleosome, presents a strong barrier to transcription in vitro. Since the discovery of the nucleosome barrier, the question of how the RNA polymerase II (Pol II) machinery overcomes nucleosomes at high speeds in vivo has remained a central question in chromatin biology. In this review, we discuss the nature of the nucleosomal barrier to transcription and highlight recent findings that provide new insights into the mechanism of transcription through nucleosomes.
DNA 包装成染色质会限制序列的可及性，从而影响包括转录在内的所有基于 DNA 的过程。事实上，染色质的基本单位核小体在体外转录中形成了强大的障碍。自从核小体障碍被发现以来，RNA 聚合酶 II（Pol II）在体内如何高速克服核小体的问题一直是染色质生物学的核心问题。在这篇综述中，我们讨论了核小体转录障碍的性质，并强调了最近的发现，这些发现为核小体转录的机制提供了新的见解。
