Transcription activation via enhanced preinitiation complex assembly in a human cell-free system lacking TAFIIs

Mol Cell. 1998 May;1(6):925-31. doi: 10.1016/s1097-2765(00)80092-1.


In contrast to previous findings in cell-free systems reconstituted with partially purified metazoan factors, we demonstrate dramatic activation of transcription in a TBP-dependent but TAFII-independent manner in HeLa nuclear extracts immunodepleted of TBP and major TAFIIs. Single-round transcription assays reveal that TAFII-independent activation is manifested at the level of productive preinitiation complex formation and that TAFIIs actually impair functional preinitiation complex assembly in a core promoter-specific manner. Furthermore, TAFIIs appear to elevate absolute levels of transcription under multiple-round transcription conditions, presumably by facilitating secondary initiation events. Finally, human coactivator activities related to those in yeast RNA polymerase II/mediator complexes appear to function in unfractionated HeLa nuclear extracts.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cell Extracts / chemistry
  • Cell Extracts / pharmacology
  • Cell-Free System
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Fungal Proteins / chemistry
  • Fungal Proteins / genetics*
  • Fungal Proteins / metabolism
  • HeLa Cells
  • Humans
  • Mediator Complex
  • Mutagenesis / physiology
  • Proline
  • Promoter Regions, Genetic / physiology
  • Protein Structure, Tertiary
  • Saccharomyces cerevisiae Proteins*
  • TATA-Binding Protein Associated Factors*
  • Trans-Activators / genetics
  • Transcription Factor TFIID*
  • Transcription Factors / chemistry
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Transcription Factors / pharmacology
  • Transcriptional Activation / drug effects
  • Transcriptional Activation / physiology*


  • Cell Extracts
  • DNA-Binding Proteins
  • Fungal Proteins
  • Gal-VP16
  • Mediator Complex
  • SRB7 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • TAF1 protein, S cerevisiae
  • TATA-Binding Protein Associated Factors
  • Trans-Activators
  • Transcription Factor TFIID
  • Transcription Factors
  • Proline