Function of TFIIIC, RNA polymerase III initiation factor, in activation and repression of tRNA gene transcription

Nucleic Acids Res. 2018 Oct 12;46(18):9444-9455. doi: 10.1093/nar/gky656.

Abstract

Transcription of transfer RNA genes by RNA polymerase III (Pol III) is controlled by general factors, TFIIIB and TFIIIC, and a negative regulator, Maf1. Here we report the interplay between TFIIIC and Maf1 in controlling Pol III activity upon the physiological switch of yeast from fermentation to respiration. TFIIIC directly competes with Pol III for chromatin occupancy as demonstrated by inversely correlated tDNA binding. The association of TFIIIC with tDNA was stronger under unfavorable respiratory conditions and in the presence of Maf1. Induction of tDNA transcription by glucose-activated protein kinase A (PKA) was correlated with the down-regulation of TFIIIC occupancy on tDNA. The conditions that activate the PKA signaling pathway promoted the binding of TFIIIB subunits, Brf1 and Bdp1, with tDNA, but decreased their interaction with TFIIIC. Association of Brf1 and Bdp1 with TFIIIC was much stronger under repressive conditions, potentially restricting TFIIIB recruitment to tDNA and preventing Pol III recruitment. Altogether, we propose a model in which, depending on growth conditions, TFIIIC promotes activation or repression of tDNA transcription.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Respiration / genetics
  • Fermentation / genetics
  • Gene Expression Regulation, Fungal
  • Gene Silencing
  • RNA Polymerase III / metabolism
  • RNA, Transfer / genetics*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Transcription Factor TFIIIB / genetics
  • Transcription Factor TFIIIB / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transcription Factors, TFIII / physiology*
  • Transcription, Genetic*
  • Transcriptional Activation / genetics

Substances

  • Bdp1 protein, S cerevisiae
  • MAF1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factor TFIIIB
  • Transcription Factors
  • Transcription Factors, TFIII
  • transcription factor TFIIIC
  • RNA, Transfer
  • RNA Polymerase III