Structure and function of the human transcription elongation factor DSIF

J Biol Chem. 1999 Mar 19;274(12):8085-92. doi: 10.1074/jbc.274.12.8085.

Abstract

5,6-Dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) is a classic inhibitor of transcription elongation by RNA polymerase II (pol II). We have previously identified and purified a novel transcription elongation factor, termed DSIF (for DRB sensitivity-inducing factor), that makes transcription sensitive to DRB. DSIF is composed of 160- and 14-kDa subunits, which are homologs of the Saccharomyces cerevisiae transcription factors Spt5 and Spt4. DSIF may either repress or stimulate transcription in vitro, depending on conditions, but its physiological function remains elusive. Here we characterize the structure and function of DSIF p160. p160 is shown to be a ubiquitous nuclear protein that forms a stable complex with p14 and interacts directly with the pol II largest subunit. Mutation analysis of p160 is used to identify structural features essential for its in vitro activity and to map the domains required for its interaction with p14 and pol II. Finally, a p160 mutant that represses DSIF activity in a dominant-negative manner is identified and used to demonstrate that DSIF represses transcription from various promoters in vivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • DNA Polymerase II / metabolism
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Nuclear Proteins / chemistry*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / physiology*
  • Peptide Mapping
  • Promoter Regions, Genetic
  • Repressor Proteins*
  • Structure-Activity Relationship
  • Transcription Factors / chemistry*
  • Transcription Factors / genetics
  • Transcription Factors / physiology*
  • Transcription, Genetic
  • Transcriptional Elongation Factors
  • Transfection

Substances

  • Nuclear Proteins
  • Repressor Proteins
  • SUPT4H1 protein, human
  • SUPT5H protein, human
  • Transcription Factors
  • Transcriptional Elongation Factors
  • DNA Polymerase II

Associated data

  • GENBANK/AB000516