TCP2 positively regulates HY5/HYH and photomorphogenesis in Arabidopsis

J Exp Bot. 2016 Feb;67(3):775-85. doi: 10.1093/jxb/erv495. Epub 2015 Nov 23.


Light regulates plant growth and development via multiple photoreceptors including phytochromes and cryptochromes. Although the functions of photoreceptors have been studied extensively, questions remain regarding the involvement of cryptochromes in photomorphogenesis. In this study, we identified a protein, TEOSINTE-LIKE1, CYCLOIDEA, and PROLIFERATING CELL FACTOR 2 (TCP2), which interacts with the cryptochrome 1 (CRY1) protein in yeast and plant cells via the N-terminal domains of both proteins. Transgenic plants overexpressing TCP2 displayed a light-dependent short hypocotyl phenotype, especially in response to blue light. Moreover, light affected TCP2 expression in a wavelength-dependent manner and TCP2 positively regulates mRNA expression of HYH and HY5. These results support the hypothesis that TCP2 is a transcription activator which acts downstream of multiple photoreceptors, including CRY1.

Keywords: Arabidopsis; CRY1; ChIP-qPCR; HY5; HYH; TCP2.; blue light signal transduction; hypocotyls.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / growth & development*
  • Arabidopsis / radiation effects*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Basic-Leucine Zipper Transcription Factors / metabolism*
  • Carrier Proteins / metabolism*
  • Cryptochromes / metabolism
  • DNA-Binding Proteins
  • Gene Expression Regulation, Plant / radiation effects
  • Light*
  • Morphogenesis / radiation effects*
  • Nuclear Proteins / metabolism*
  • Phenotype
  • Plant Cells / metabolism
  • Plant Cells / radiation effects
  • Plants, Genetically Modified
  • Protein Binding / radiation effects
  • Saccharomyces cerevisiae / metabolism
  • Signal Transduction / radiation effects
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*


  • Arabidopsis Proteins
  • Basic-Leucine Zipper Transcription Factors
  • CRY1 protein, Arabidopsis
  • Carrier Proteins
  • Cryptochromes
  • DNA-Binding Proteins
  • HY5 protein, Arabidopsis
  • HYH protein, Arabidopsis
  • Nuclear Proteins
  • TCP2 protein, Arabidopsis
  • Transcription Factors