A plant-specific transcription factor IIB-related protein, pBRP2, is involved in endosperm growth control

PLoS One. 2011 Feb 24;6(2):e17216. doi: 10.1371/journal.pone.0017216.


General transcription factor IIB (TFIIB) and TFIIB-related factor (BRF), are conserved RNA polymerase II/III (RNAPII/III) selectivity factors that are involved in polymerase recruitment and transcription initiation in eukaryotes. Recent findings have shown that plants have evolved a third type of B-factor, plant-specific TFIIB-related protein 1 (pBRP1), which seems to be involved in RNAPI transcription. Here, we extend the repertoire of B-factors in plants by reporting the characterization of a novel TFIIB-related protein, plant-specific TFIIB-related protein 2 (pBRP2), which is found to date only in the Brassicacea family. Unlike other B-factors that are ubiquitously expressed, PBRP2 expression is restricted to reproductive organs and seeds as shown by RT-PCR, immunofluorescence labelling and GUS staining experiments. Interestingly, pbrp2 loss-of-function specifically affects the development of the syncytial endosperm, with both parental contributions required for wild-type development. pBRP2, is the first B-factor to exhibit cell-specific expression and regulation in eukaryotes, and might play a role in enforcing bi-parental reproduction in angiosperms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / genetics
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / genetics
  • Brassicaceae / genetics
  • Brassicaceae / growth & development
  • Brassicaceae / metabolism
  • Endosperm / genetics*
  • Endosperm / growth & development*
  • Endosperm / metabolism
  • Gene Expression Regulation, Developmental / physiology
  • Gene Expression Regulation, Plant / physiology
  • Molecular Sequence Data
  • Phylogeny
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Plant Proteins / physiology*
  • Plants, Genetically Modified
  • Seeds / genetics
  • Seeds / growth & development
  • Sequence Homology
  • Species Specificity
  • Transcription Factor TFIIB / chemistry
  • Transcription Factors / chemistry
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transcription Factors / physiology*


  • Arabidopsis Proteins
  • Plant Proteins
  • Transcription Factor TFIIB
  • Transcription Factors
  • transcription factor IIB-related protein, Arabidopsis