The John Curtin School of Medical Research, The Australian National University, PO Box 334, Canberra, ACT 2601, Australia.
The John Curtin School of Medical Research, The Australian National University, PO Box 334, Canberra, ACT 2601, Australia.
Trends Genet. 2014 May;30(5):199-209. doi: 10.1016/j.tig.2014.03.002. Epub 2014 Apr 23.
The function of a eukaryotic cell crucially depends on accurate gene transcription to ensure the right genes are expressed whereas unrequired genes are repressed. Therefore, arguably, one of the most important regions in the genome is the transcription start-site (TSS) of protein-coding and non-coding genes. Until recently, understanding the mechanisms that define the location of the TSS and how it is created has largely focused on the role of DNA sequence-specific transcription factors. However, within the nucleus of a eukaryotic cell, transcription occurs in a highly compacted nucleosomal environment, and it is becoming clear that accessibility of the TSS is a key controlling step in transcriptional regulation. It has traditionally been thought that transcription can only proceed once the nucleosomes at the TSS have been evicted. New work suggests otherwise, however, and the focus of this review is to challenge this belief.
真核细胞的功能在很大程度上取决于准确的基因转录，以确保正确的基因得到表达，而不需要的基因则受到抑制。因此，可以说，基因组中最重要的区域之一是蛋白质编码和非编码基因的转录起始位点（TSS）。直到最近，人们对定义 TSS 位置的机制以及它是如何产生的理解主要集中在 DNA 序列特异性转录因子的作用上。然而，在真核细胞的核内，转录发生在高度浓缩的核小体环境中，现在越来越清楚的是，TSS 的可及性是转录调控的一个关键控制步骤。传统上认为，只有当 TSS 处的核小体被逐出后，转录才能进行。然而，新的研究表明并非如此，本综述的重点是对这一观点提出质疑。
