Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Differential patterns of intronic and exonic DNA regions with respect to RNA polymerase II occupancy, nucleosome density and H3K36me3 marking in fission yeast. | Wilhelm et al. Genome Biology 2011 12 R82 http 2011 12 8 R82 Genome Biology RESEARCH Open Access Differential patterns of intronie and exonie DNA regions with respect to RNA polymerase II oeeupaney nucleosome density and H3K36me3 marking in fission yeast 1 13 1 1 Brian T Wilhelm Samuel Marguerat Sofia Aligianni Sandra Codlin Stephen Watt and Jurg Bahler Abstract Background The generation of mature mRNAs involves interconnected processes including transcription by RNA polymerase II Pol II modification of histones and processing of pre-mRNAs through capping intron splicing and polyadenylation. These processes are thought to be integrated both spatially and temporally but it is unclear how these connections manifest at a global level with respect to chromatin patterns and transcription kinetics. We sought to clarify the relationships between chromatin transcription and splicing using multiple genome-wide approaches in fission yeast. Results To investigate these functional interdependencies we determined Pol II occupancy across all genes using high-density tiling arrays. We also performed ChIP-chip on the same array platform to globally map histone H3 and its H3K36me3 modification complemented by formaldehyde-assisted isolation of regulatory elements FAIRE . Surprisingly Pol II occupancy was higher in introns than in exons and this difference was inversely correlated with gene expression levels at a global level. Moreover introns showed distinct distributions of histone H3 H3K36me3 and FAIRE signals similar to those at promoters and terminators. These distinct transcription and chromatin patterns of intronic regions were most pronounced in poorly expressed genes. Conclusions Our findings suggest that Pol II accumulates at the 3 ends of introns leading to substantial transcriptional delays in weakly transcribed genes. We propose that the global relationship between transcription chromatin remodeling and splicing may reflect differences in local
