Gene loops enhance transcriptional directionality
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Sue Mei Tan-Wong Judith B Zaugg Jurgi Camblong Zhenyu Xu David W Zhang Hannah E Mischo Aseem Z Ansari Nicholas Luscombe Lars M Steinmetz Nick J ProudfootAbstract
Eukaryotic genomes are extensively transcribed, forming both messenger RNAs (mRNAs) and noncoding RNAs (ncRNAs). ncRNAs made by RNA polymerase II often initiate from bidirectional promoters (nucleosome-depleted chromatin) that synthesize mRNA and ncRNA in opposite directions. We demonstrate that, by adopting a gene-loop conformation, actively transcribed mRNA encoding genes restrict divergent transcription of ncRNAs. Because gene-loop formation depends on a protein factor (Ssu72) that coassociates with both the promoter and the terminator, the inactivation of Ssu72 leads to increased synthesis of promoter-associated divergent ncRNAs, referred to as Ssu72-restricted transcripts (SRTs). Similarly, inactivation of individual gene loops by gene mutation enhances SRT synthesis. We demonstrate that gene-loop conformation enforces transcriptional directionality on otherwise bidirectional promoters.
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Publisher website (DOI) 10.1126/science.1224350
Europe PubMed Central 23019609
Pubmed 23019609
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