tailieunhanh - Báo cáo y học: "Global nucleosome distribution and the regulation of transcription in yeas"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Global nucleosome distribution and the regulation of transcription in yeast. | Minireview Global nucleosome distribution and the regulation of transcription in yeast Sevinc Ercan Michael J Carrozza and Jerry L Workman Addresses Stowers Institute for Medical Research 1 000 East 50th Street Kansas City MO 64110 USA. Department of Biochemistry and Molecular Biology The Pennsylvania State University University Park PA 16802 USA. Correspondence Jerry L Workman. E-mail JLW@ Published 30 September 2004 Genome Biology 2004 5 243 The electronic version of this article is the complete one and can be found online at http 2004 5 10 243 2004 BioMed Central Ltd Abstract Recent studies show that active regulatory regions of the yeast genome have a lower density of nucleosomes than other regions and that there is an inverse correlation between nucleosome density and the transcription rate of a gene. This may be the result of transcription factors displacing nucleosomes. It has been known for nearly three decades that there is a relationship between the chromatin structure of a gene and its transcriptional status. This relationship was first identified when nuclease-hypersensitive sites were observed to appear at the 5 end of genes upon activation of transcription 1 2 . Later the transcription-dependent changes in the chromatin of a gene came to be understood better through examination of the chromatin structures of individual genes - such as PHO5 GAL1 and GAL10 - under active and inactive conditions 3-7 . These studies found that the nucleosomes -the basic repeating units of chromatin each consisting of a histone octamer encircled by about 146 base-pairs of DNA -are modified unfolded or lost at the promoters of genes upon activation of transcription. It remains unclear however whether such remodeling or loss of nucleosomes is a general feature of eukaryotic gene regulation. Recently two papers have analyzed the nucleosome distribution throughout the yeast genome. The authors of the new studies 8 9 propose that the .