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Figure 8 | BMC Biology

Figure 8

From: Compromised RNA polymerase III complex assembly leads to local alterations of intergenic RNA polymerase II transcription in Saccharomyces cerevisiae

Figure 8

Model for the appearance of 5'-extended and de-repressed Pol II transcripts in Pol III complex mutants. In wild type cells, the bidirectional activity of transcription factor binding sites at some promoters is inhibited by the presence of a nearby fully or partially assembled Pol III complex (for example, ETC site). Compromised Pol III complex formation allows Pol II transcription factors to bidirectionally load Pol II preinitiation complexes (PIC). These events lead to the creation of aberrant transcription start sites (TSS), resulting in the extension of the 5'-UTR of the divergent gene. Upstream initiating Pol II may also inhibit normal PIC formation by transcriptional interference. This scenario may also be involved in the de-repression of SPO74 (and other intergenic regions adjacent to tDNAs) observed when Pol III assembly at an upstream tDNA is compromised. In this case the aberrant transcript reads through chromatin-bound factors responsible for repression of SPO74 in haploid cells. Pol II, polymerase II; Pol III, polymerase III.

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BMC Biology

ISSN: 1741-7007

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