Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Chromatin ‘programming’ by sequence - is there more to the nucleosome code than %GC? | Journal of Biology Minireview Chromatin programming by sequence - is there more to the nucleosome code than gC Amanda Hughes and Oliver J Rando Address Department of Biochemistry and Molecular Pharmacology University of Massachusetts Medical School 364 Plantation Street No. 903 Worcester MA 01605 USA. Correspondence Oliver Rando. Email Abstract The role of genomic sequence in directing the packaging of eukaryotic genomes into chromatin has been the subject of considerable recent debate. A new paper from Tillo and Hughes shows that the intrinsic thermodynamic preference of a given sequence in the yeast genome for the histone octamer can largely be captured with a simple model and in fact is mostly explained by GC. Thus the rules for predicting nucleosome occupancy from genomic sequence are much less complicated than has been claimed. See research article http 1471-2105 10 442. Packaging of eukaryotic DNA into nucleosomes has profound effects on DNA-templated processes. The 147 bp of DNA wrapped around the histone octamer is generally believed to be less accessible to DNA-binding proteins than is the DNA between nucleosomes. The positioning of nucleosomes relative to underlying sequences therefore has considerable implications for the regulation of gene expression and understanding where nucleosomes are located and the rules underlying nucleosome positioning are key questions in understanding transcriptional control. The recent revolution in genomics technologies has made genome-wide mapping of nucleosome positions possible in organisms ranging from budding yeast to humans. These genome-wide maps provide us with a multitude of hypotheses regarding the role of nucleosome positioning in gene regulation reviewed in 1-3 . Perhaps one of the biggest surprises from even the earliest of these mapping efforts in Saccharomyces cerevisiae was the observation that the majority of nucleosomes are well positioned that is that .
