转录（一个细胞的DNA模板的一个序列的互补性RNA版本的生成）正在成为一个比仅仅在几年前所认为的要更为复杂的过程。例如，“RNA聚合酶暂停”是普遍存在的，从而为各种不同调控过程提供一个焦点，而且很多转录副本注定要迅速退化。为了研究这些现象，Stirling Churchman 和 Jonathan Weissman建立了一种被称为“native elongating transcript sequencing (NET-seq)”的方法，该方法能够以单核苷酸分辨率对转录进行量化。NET-seq基于对与从活细胞直接获取的“RNA聚合酶-II”相关的新生副本进行测序。他们利用这一新方法对酿酒酵母的聚合酶暂停和回撤以及转录的方向性进行了研究。（生物谷Bioon.com）
生物谷推荐原文出处：
Nature doi:10.1038/nature09652
Nascent transcript sequencing visualizes transcription at nucleotide resolution
L. Stirling Churchman& Jonathan S. Weissman
Recent studies of transcription have revealed a level of complexity not previously appreciated even a few years ago, both in the intricate use of post-initiation control and the mass production of rapidly degraded transcripts. Dissection of these pathways requires strategies for precisely following transcripts as they are being produced. Here we present an approach (native elongating transcript sequencing, NET-seq), based on deep sequencing of 3′ ends of nascent transcripts associated with RNA polymerase, to monitor transcription at nucleotide resolution. Application of NET-seq in Saccharomyces cerevisiae reveals that although promoters are generally capable of divergent transcription, the Rpd3S deacetylation complex enforces strong directionality to most promoters by suppressing antisense transcript initiation. Our studies also reveal pervasive polymerase pausing and backtracking throughout the body of transcripts. Average pause density shows prominent peaks at each of the first four nucleosomes, with the peak location occurring in good agreement with in vitro biophysical measurements. Thus, nucleosome-induced pausing represents a major barrier to transcriptional elongation in vivo.
