Rapid reversion from monomer to dimer regenerates the ultraviolet-B photoreceptor UV RESISTANCE LOCUS8 in intact arabidopsis plants

Heilmann, M. and Jenkins, G.I. (2013) Rapid reversion from monomer to dimer regenerates the ultraviolet-B photoreceptor UV RESISTANCE LOCUS8 in intact arabidopsis plants. Plant Physiology, 161(1), pp. 547-555. (doi:10.1104/pp.112.206805)

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Abstract

Arabidopsis (Arabidopsis thaliana) UV RESISTANCE LOCUS8 (UVR8) is a photoreceptor that specifically mediates photomorphogenic responses to ultraviolet (UV)-B in plants. UV-B photoreception induces the conversion of the UVR8 dimer into a monomer that interacts with the CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) protein to regulate gene expression. However, it is not known how the dimeric photoreceptor is regenerated in plants. Here, we show, by using inhibitors of protein synthesis and degradation via the proteasome, that the UVR8 dimer is not regenerated by rapid de novo synthesis following destruction of the monomer. Rather, regeneration occurs by reversion from the monomer to the dimer. However, regeneration of dimeric UVR8 in darkness following UV-B exposure occurs much more rapidly in vivo than in vitro with illuminated plant extracts or purified UVR8, indicating that rapid regeneration requires intact cells. Rapid dimer regeneration in vivo requires protein synthesis, the presence of a carboxyl-terminal 27-amino acid region of UVR8, and the presence of COP1, which is known to interact with the carboxyl-terminal region. However, none of these factors can account fully for the difference in regeneration kinetics in vivo and in vitro, indicating that additional proteins or processes are involved in UVR8 dimer regeneration in vivo.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Heilmann, Miss Monika and Jenkins, Professor Gareth
Authors: Heilmann, M., and Jenkins, G.I.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Plant Physiology
Publisher:American Society of Plant Biologists
ISSN:0032-0889
Published Online:01 November 2012
Copyright Holders:Copyright © 2012 American Society of Plant Biologists
First Published:First published in Plant Physiology 161(1):547-555
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
497051Quest for the Holy Grail of plant photobiology: a UV-B photoreceptorGareth JenkinsLeverhulme Trust (LEVERHULME)F/00179/AZRI MOLECULAR CELL & SYSTEMS BIOLOGY