stochastic and regulatory role of chromatin silencing in genomic response to environmental changes随机和监管的作用在基因组染色质沉默应对环境变化.pdfVIP

Stochastic and Regulatory Role of Chromatin Silencing in Genomic Response to Environmental Changes 1 2 1 Jung Kyoon Choi , Sohyun Hwang , Young-Joon Kim * 1 Department of Biochemistry, Yonsei University, Seoul, Republic of Korea, 2 Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea Abstract Phenotypic diversity and fidelity can be balanced by controlling stochastic molecular mechanisms. Epigenetic silencing is one that has a critical role in stress response. Here we show that in yeast, incomplete silencing increases stochastic noise in gene expression, probably owing to unstable chromatin structure. Telomere position effect is suggested as one mechanism. Expression diversity in a population achieved in this way may render a subset of cells to readily respond to various acute stresses. By contrast, strong silencing tends to suppress noisy expression of genes, in particular those involved in life cycle control. In this regime, chromatin may act as a noise filter for precisely regulated responses to environmental signals that induce huge phenotypic changes such as a cell fate transition. These results propose modulation of chromatin stability as an important determinant of environmental adaptation and cellular differentiation. Citation: Choi JK, Hwang S, Kim Y-J (2008) Stochastic and Regulatory Role of Chromatin Silencing in Genomic Response to Environmental Changes. PLoS ONE 3(8): e3002. doi:10.1371/journal.pone.0003002 Editor: Eshel Ben-Jacob, Tel Aviv University, Israel Received May 19, 2008; Accepted July 29, 2008; Published August 20, 2008 Copyright: 2008 Choi et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided