A new class of transcription factors mediates brassinosteroid-regulated gene expression in Arabidopsis

Cell. 2005 Jan 28;120(2):249-59. doi: 10.1016/j.cell.2004.11.044.

Abstract

Brassinosteroids (BRs) signal through a plasma membrane-localized receptor kinase to regulate plant growth and development. We showed previously that a novel protein, BES1, accumulates in the nucleus in response to BRs, where it plays a role in BR-regulated gene expression; however, the mechanism by which BES1 regulates gene expression is unknown. In this study, we dissect BES1 subdomains and establish that BES1 is a transcription factor that binds to and activates BR target gene promoters both in vitro and in vivo. BES1 interacts with a basic helix-loop-helix protein, BIM1, to synergistically bind to E box (CANNTG) sequences present in many BR-induced promoters. Loss-of-function and gain-of-function mutants of BIM1 and its close family members display BR response phenotypes. Thus, BES1 defines a new class of plant-specific transcription factors that cooperate with transcription factors such as BIM1 to regulate BR-induced genes.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism*
  • Cell Nucleus / metabolism
  • DNA-Binding Proteins
  • Gene Expression Regulation, Plant / physiology*
  • Helix-Loop-Helix Motifs / physiology
  • Molecular Sequence Data
  • Nuclear Proteins / metabolism
  • Phytosterols / metabolism*
  • Transcription Factors / metabolism*

Substances

  • Arabidopsis Proteins
  • BES1 protein, Arabidopsis
  • DNA-Binding Proteins
  • Nuclear Proteins
  • Phytosterols
  • Transcription Factors