bHLH class transcription factors take centre stage in phytochrome signalling

Trends Plant Sci. 2005 Feb;10(2):51-4. doi: 10.1016/j.tplants.2004.12.005.


The phytochrome family of photoreceptors (there are five phytochromes in Arabidopsis, named phyA to phyE) maximally absorbs red and far-red light and plays important functions throughout the life cycle of plants. Several recent studies have shown that multiple related bHLH (basic helix-loop-helix) class transcription factors play key roles in phytochrome signal transduction. Somewhat surprisingly these transcription factors primarily act as negative regulators of phytochrome signalling. Moreover, in some cases, the phytochromes inhibit those negative regulators.

Publication types

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

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / metabolism
  • Helix-Loop-Helix Motifs
  • Phytochrome / genetics
  • Phytochrome / physiology*
  • Signal Transduction
  • Transcription Factors / metabolism*


  • Arabidopsis Proteins
  • Transcription Factors
  • Phytochrome