核小体在外显子中定位良好,并带有特征性的组蛋白修饰。

Nucleosomes are well positioned in exons and carry characteristic histone modifications.

作者信息

Andersson Robin, Enroth Stefan, Rada-Iglesias Alvaro, Wadelius Claes, Komorowski Jan

机构信息

The Linnaeus Centre for Bioinformatics, Uppsala University, Sweden.

出版信息

Genome Res. 2009 Oct;19(10):1732-41. doi: 10.1101/gr.092353.109. Epub 2009 Aug 17.

Abstract

The genomes of higher organisms are packaged in nucleosomes with functional histone modifications. Until now, genome-wide nucleosome and histone modification studies have focused on transcription start sites (TSSs) where nucleosomes in RNA polymerase II (RNAPII) occupied genes are well positioned and have histone modifications that are characteristic of expression status. Using public data, we here show that there is a higher nucleosome-positioning signal in internal human exons and that this positioning is independent of expression. We observed a similarly strong nucleosome-positioning signal in internal exons of Caenorhabditis elegans. Among the 38 histone modifications analyzed in man, H3K36me3, H3K79me1, H2BK5me1, H3K27me1, H3K27me2, and H3K27me3 had evidently higher signals in internal exons than in the following introns and were clearly related to exon expression. These observations are suggestive of roles in splicing. Thus, exons are not only characterized by their coding capacity, but also by their nucleosome organization, which seems evolutionarily conserved since it is present in both primates and nematodes.

摘要

高等生物的基因组被包装在具有功能性组蛋白修饰的核小体中。到目前为止,全基因组范围的核小体和组蛋白修饰研究主要集中在转录起始位点(TSS),在RNA聚合酶II(RNAPII)占据的基因中,核小体定位良好,并且具有表达状态特征性的组蛋白修饰。利用公开数据,我们在此表明,人类内部外显子中存在更高的核小体定位信号,并且这种定位与表达无关。我们在秀丽隐杆线虫的内部外显子中观察到了类似强烈的核小体定位信号。在对人类分析的38种组蛋白修饰中,H3K36me3、H3K79me1、H2BK5me1、H3K27me1、H3K27me2和H3K27me3在内部外显子中的信号明显高于随后的内含子,并且与外显子表达明显相关。这些观察结果提示其在剪接中发挥作用。因此,外显子不仅以其编码能力为特征,还以其核小体组织为特征,这似乎在进化上是保守的,因为它在灵长类动物和线虫中都存在。

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