Project description:In the yeast genome, a large proportion of nucleosomes occupy well-defined positions. While the contribution of chromatin remodelers and DNA binding proteins to maintain this organization is well established, the relevance of the DNA sequence to nucleosome positioning in the genomic context remains controversial. Through genome-wide, quantitative analysis of nucleosome positioning and high-resolution mutagenenesis of mononucleosomal DNA, we show that sequence changes distort the nucleosomal pattern at the level of individual nucleosomes. This effect is equally detected in transcribed and non-transcribed regions, suggesting the existence of sequence elements contributing to positioning. To identify such elements, we incorporated information from nucleosomal signatures into artificial synthetic DNA molecules and found that they generated regular nucleosomal arrays indistinguishable from those of endogenous sequences. Strikingly, this information is species-specific and can be combined with coding information through the use of synonymous codons such that genes from one species can be engineered to adopt the nucleosomal organization of another. These findings open up the possibility of designing coding and non-coding DNA molecules capable of directing their own nucleosomal organization.
Project description:This study reveals widespread Pol II pausing at single-nucleotide resolution across the human genome with the majority of Pol II pauses occur outside of promoter-proximal gene regions primarily along the gene-body of transcribed genes. We show DNA sequence properties underlying widespread transcriptional pausing including a new pause motif. The study indicates pervasive sequence-induced transcriptional pausing in human cells.