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真核生物基因组中基因排列的模式、启动子结构和基因表达稳定性

已有 5478 次阅读 2011-2-28 11:03 |个人分类:翻译作品|系统分类:论文交流| 双向启动子, 基因组排列, 核小体锚定

真核生物基因组中基因排列的模式、启动子结构和基因表达稳定性的关系

 

熊荣川

摘要:

    基因表达的稳定性和可进化性之间的平衡对于生物体的长期维持非常重要。本文中,我们研究了启动子的遗传和表观遗传特性是否对基因的表达变动性有所影响。我们假设相邻基因的方向性(首尾相连或头对头相连)以及基因上游序列的长度对启动子的结构和基因表达的变动性很重要。我们的研究发现,在芽殖酵母的基因组中,上游距离(和相邻基因的距离)短的基因,其表达变动性较小,启动子两端有强锚定的核小体,启动子上锚定的核小体较少。观察结果表明,两端强锚定的核小体可能消耗了启动子的核小体的锚定特性从而使得基因表达变得稳定。平均而言,头对头排列的基因较头尾相连的基因,有更低的基因表达变动性、更强的启动子两端锚定核小体、更强的启动子核心区域的核小体锚定不应性。在各种真核生物基因组,有同样的观察结果。在类似哺乳动物的复杂生物体内,只有一小部分头尾相连的基因有较短的上游序列距离,这可能是由于这些基因上游启动子两端没有强锚定的核小体的关系。

关键词:双向启动子 基因组排列 核小体锚定

 

Gene clustering pattern--promoter architecture and gene expression stability in eukaryotic genomes

 

Abstract

A balance between gene expression stability and evolvability is essential for the long-term maintenance of a living system. In this paper, we studied whether the genetic and epigenetic properties of the promoter affect gene expression variability. We hypothesized that upstream distance and orientation (head-to-head or head-to-tail) are important for the promoter architecture and gene expression variability. We found that in budding yeast genes with a short upstream distance tend to have low gene expression variability, and their promoter is flanked by strongly positioned nucleosomes and tends to have low nucleosome occupancy. These observations suggest that in vivo positioning of the flanking nucleosomes facilitates stable nucleosome depletion at the core promoter region and enhances gene expression stability. Head-to-head genes have, on average, lower gene expression variability, greater nucleosome depletion at the core promoter region, and more strongly positioned nucleosomes that flank the core promoter than do head-to-tail genes. These observations hold for diverse eukaryotes. In complex organisms such as mammals, only a small fraction of head-to-tail genes have retained a short upstream distance, probably because the promoter may not be flanked by a strongly positioned nucleosome on the upstream side. (Woo et al., 2011)

Keywords: bi-directional promoters; genome organization; nucleosome positioning

 

参考文献

 

Gene clustering pattern--promoter architecture and gene expression stability in .pdf

Woo Yong H.,Li Wen-Hsiung (2011). "Gene clustering pattern, promoter architecture, and gene expression stability in eukaryotic genomes." Proceedings of the National Academy of Sciences 108(8): 3306-3311.

 

 

 



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