Choi Jung Kyoon, Kim Young-Joon
Department of Biochemistry, Yonsei University, Seodaemun-Gu, Seoul, Korea.
Nat Genet. 2009 Apr;41(4):498-503. doi: 10.1038/ng.319. Epub 2009 Mar 1.
Variation in gene expression is an essential material for biological diversity among single cells, individuals and populations or species. Here we show that expression variability is an intrinsic property that persists at those different levels. Each promoter seems to have a unique capacity to respond to external signals that can be environmental, genetic or even stochastic. Our investigation into nucleosome organization of variably responding promoters revealed a commonly positioned nucleosome at a critical regulatory region where most transcription start sites and TATA elements are located, a deviation from typical nucleosome-free status. The nucleotide sequences in this region of variable promoters showed a high propensity for DNA bending and a periodic distribution of particular dinucleotides, encoding preferences for DNA-nucleosome interaction. Variable expression is likely to occur during removal of this nucleosome for gene activation. This is a unique example of how promoter sequences intrinsically encode regulatory flexibility, which is vital for biological processes such as adaptation, development and evolution.
基因表达的变化是单细胞、个体、种群或物种间生物多样性的重要物质基础。在此我们表明，表达变异性是一种内在属性，在这些不同层面上持续存在。每个启动子似乎都有独特的能力来响应外部信号，这些信号可以是环境的、遗传的甚至是随机的。我们对可变响应启动子的核小体组织的研究揭示，在大多数转录起始位点和TATA元件所在的关键调控区域存在一个常见定位的核小体，这偏离了典型的无核小体状态。可变启动子这一区域的核苷酸序列显示出DNA弯曲的高倾向以及特定二核苷酸的周期性分布，编码了对DNA-核小体相互作用的偏好。可变表达可能在为激活基因而去除该核小体的过程中发生。这是启动子序列如何内在地编码调控灵活性的一个独特例子，而调控灵活性对于诸如适应、发育和进化等生物过程至关重要。
