Dr1 (NC2) is present at tRNA genes and represses their transcription in human cells

Nucleic Acids Res. 2010 Mar;38(4):1228-39. doi: 10.1093/nar/gkp1102. Epub 2009 Dec 3.

Abstract

Dr1 (also known as NC2beta) was identified as a repressor of RNA polymerase (pol) II transcription. It was subsequently shown to inhibit pol III transcription when expressed at high levels in vitro or in yeast cells. However, endogenous Dr1 was not detected at pol III-transcribed genes in growing yeast. In contrast, we demonstrate that endogenous Dr1 is present at pol III templates in human cells, as is its dimerization partner DRAP1 (also called NC2alpha). Expression of tRNA by pol III is selectively enhanced by RNAi-mediated depletion of endogenous human Dr1, but we found no evidence that DRAP1 influences pol III output in vivo. A stable association was detected between endogenous Dr1 and the pol III-specific transcription factor Brf1. This interaction may recruit Dr1 to pol III templates in vivo, as crosslinking to these sites increases following Brf1 induction. On the basis of these data, we conclude that the physiological functions of human Dr1 include regulation of pol III transcription.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CHO Cells
  • Cell Line
  • Cricetinae
  • Cricetulus
  • Gene Expression Regulation*
  • Humans
  • Phosphoproteins / antagonists & inhibitors
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • RNA Interference
  • RNA Polymerase III / metabolism
  • RNA, Transfer / biosynthesis
  • RNA, Transfer / genetics*
  • Repressor Proteins / analysis
  • Repressor Proteins / metabolism*
  • Transcription Factor TFIIIB / metabolism
  • Transcription Factors / antagonists & inhibitors
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcription, Genetic

Substances

  • DRAP1 protein, human
  • Phosphoproteins
  • Repressor Proteins
  • Transcription Factor TFIIIB
  • Transcription Factors
  • down-regulator of transcription 1
  • RNA, Transfer
  • RNA Polymerase III