RNA Polymerase III Subunit POLR3G Regulates Specific Subsets of PolyA + and SmallRNA Transcriptomes and Splicing in Human Pluripotent Stem Cells

Stem Cell Reports. 2017 May 9;8(5):1442-1454. doi: 10.1016/j.stemcr.2017.04.016.

Abstract

POLR3G is expressed at high levels in human pluripotent stem cells (hPSCs) and is required for maintenance of stem cell state through mechanisms not known in detail. To explore how POLR3G regulates stem cell state, we carried out deep-sequencing analysis of polyA+ and smallRNA transcriptomes present in hPSCs and regulated in POLR3G-dependent manner. Our data reveal that POLR3G regulates a specific subset of the hPSC transcriptome, including multiple transcript types, such as protein-coding genes, long intervening non-coding RNAs, microRNAs and small nucleolar RNAs, and affects RNA splicing. The primary function of POLR3G is in the maintenance rather than repression of transcription. The majority of POLR3G polyA+ transcriptome is regulated during differentiation, and the key pluripotency factors bind to the promoters of at least 30% of the POLR3G-regulated transcripts. Among the direct targets of POLR3G, POLG is potentially important in sustaining stem cell status in a POLR3G-dependent manner.

Keywords: human embryonic stem cell; mitochondria; pluripotency; polyA(+) RNA; polymerase III; smallRNA; splicing; transcriptome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • DNA Polymerase gamma / genetics
  • DNA Polymerase gamma / metabolism
  • Human Embryonic Stem Cells / metabolism*
  • Humans
  • Induced Pluripotent Stem Cells / metabolism*
  • Polyadenylation*
  • RNA Polymerase III / genetics
  • RNA Polymerase III / metabolism*
  • RNA Splicing*
  • RNA, Small Untranslated / genetics*
  • RNA, Small Untranslated / metabolism
  • Transcriptome*

Substances

  • RNA, Small Untranslated
  • POLR3G protein, human
  • RNA Polymerase III
  • DNA Polymerase gamma
  • POLG protein, human