Scientific article
English

CONSTITUTIVELY PHOTOMORPHOGENIC1 is required for the UV-B response in Arabidopsis

Published inThe Plant cell, vol. 18, no. 8, p. 1975-1990
Publication date2006
Abstract

CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) is a negative regulator of photomorphogenesis in Arabidopsis thaliana. COP1 functions as an E3 ubiquitin ligase, targeting select proteins for proteasomal degradation in plants as well as in mammals. Among its substrates is the basic domain/leucine zipper (bZIP) transcription factor ELONGATED HYPOCOTYL5 (HY5), one of the key regulators of photomorphogenesis under all light qualities, including UV-B responses required for tolerance to this environmental threat. Here, we report that, in contrast with the situation in visible light, COP1 is a critical positive regulator of responses to low levels of UV-B. We show that in the cop1-4 mutant, flavonoid accumulation and genome-wide expression changes in response to UV-B are blocked to a large extent. COP1 is required for HY5 gene activation, and both COP1 and HY5 proteins accumulate in the nucleus under supplementary UV-B. SUPPRESSOR OF PHYTOCHROME A-105 family proteins (SPA1 to SPA4) that are required for COP1 function in dark and visible light are not essential in the response to UV-B. We conclude that COP1 performs a specific and novel role in the plants' photomorphogenic response to UV-B, coordinating HY5-dependent and -independent pathways, which eventually results in UV-B tolerance.

Keywords
  • Arabidopsis/enzymology/genetics/radiation effects
  • Arabidopsis Proteins/genetics/metabolism/physiology
  • Basic-Leucine Zipper Transcription Factors/metabolism
  • Cell Nucleus/metabolism
  • Flavonoids/metabolism
  • Gene Expression Regulation, Plant/radiation effects
  • Genes, Plant
  • Hypocotyl/growth & development/metabolism/radiation effects
  • Mutation
  • Nuclear Proteins/metabolism
  • Transcriptional Activation
  • Ubiquitin-Protein Ligases/genetics/metabolism/physiology
  • Ultraviolet Rays
Affiliation entities Not a UNIGE publication
Citation (ISO format)
ORAVECZ, Attila et al. CONSTITUTIVELY PHOTOMORPHOGENIC1 is required for the UV-B response in Arabidopsis. In: The Plant cell, 2006, vol. 18, n° 8, p. 1975–1990. doi: 10.1105/tpc.105.040097
Main files (1)
Article (Published version)
accessLevelRestricted
Identifiers
ISSN of the journal1040-4651
611views
0downloads

Technical informations

Creation29/03/2012 12:28:00
First validation29/03/2012 12:28:00
Update time14/03/2023 17:22:02
Status update14/03/2023 17:22:02
Last indexation29/10/2024 19:18:42
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack