Nucleosome free regions (NFRs) at the 5'- and 3'-end of genes are general sites of transcription initiation for mRNA and non-coding RNA (ncRNA). The presence of NFRs within transcriptional regulatory regions and the conserved location of transcription start sites at NFRs strongly suggest the regulation of NFRs profoundly affects transcription initiation. To date, multiple factors are known to facilitate transcription initiation by positively regulating the formation and/or size of NFRs in vivo. However, mechanisms to repress transcription by negatively regulating the size of NFRs have not been identified. We identified four distinct classes of NFRs located at the 5'-and 3'-end of genes, within ORFs, and far from ORFs. The ATP-dependent chromatin remodeling enzyme Isw2 was enriched at all classes of NFRs. Analysis of RNA levels also demonstrated Isw2 is required to repress ncRNA transcription from many of these NFRs. Thus by the systematic annotation of NFRs across the yeast genome and analysis of ncRNA transcription, we establish, for the first time, a mechanism by which NFR size is negatively regulated to repress ncRNA transcription from NFRs. Finally, we provide evidence suggesting one biological consequence for repression of ncRNA, by Isw2 or the exosome, prevents transcriptional interference of mRNA.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|