RNA polymerase II (RNAP II)-associated factors are recruited to tRNA loci, revealing that RNAP II- and RNAP III-mediated transcriptions overlap in yeast.
In yeast (Saccharomyces cerevisiae), the synthesis of tRNAs by RNA polymerase III (RNAP III) down-regulates the transcription of the nearby RNAP II-transcribed genes by a mechanism that is poorly understood. To clarify the basis of this tRNA gene-mediated (TGM) silencing, here, conducting a bioinformatics analysis of available ChIP-chip and ChIP-sequencing genomic data from yeast, we investigated whether the RNAP III transcriptional machinery can recruit protein factors required for RNAP II transcription. An analysis of 46 genome-wide protein-density profiles revealed that 12 factors normally implicated in RNAP II-mediated gene transcription are more enriched at tRNA than at mRNA loci. These 12 factors typically have RNA-binding properties, participate in the termination stage of the RNAP II transcription, and preferentially localize to the tRNA loci by a mechanism that apparently is based on the RNAP III transcription level. The factors included two kinases of RNAP II (Bur1 and Ctk1), a histone demethylase (Jhd2), and a mutated form of a nucleosome-remodeling factor (Spt6) that have never been reported to be recruited to tRNA loci. Moreover, we show that the expression levels of RNAP II-transcribed genes downstream of tRNA loci correlate with the distance from the tRNA gene by a mechanism that depends on their orientation. These results are consistent with the notion that pre-tRNAs recruit RNAP II-associated factors, thereby reducing the availability of these factors for RNAP II transcription and contributing, at least in part, to the TGM-silencing mechanism.
['Trotta|Edoardo|E|']
D018844:Cyclin-Dependent Kinases D056426:Genetic Loci D056488:Histone Chaperones D011494:Protein Kinases D012319:RNA Polymerase II D012331:RNA, Fungal D012333:RNA, Messenger D012343:RNA, Transfer D012441:Saccharomyces cerevisiae D029701:Saccharomyces cerevisiae Proteins D014158:Transcription, Genetic D035602:Transcriptional Elongation Factors
RNA polymerase II RNA polymerase III RNA-binding protein chromatin immunoprecipitation (ChiP) gene regulation gene silencing genome-wide transcription precursor tRNA (pre-tRNA) transcriptomics transfer RNA (tRNA)