Regulation of transcription by Ultraviolet-B radiation in Arabidopsis thaliana

Velanis, Christos N. (2015) Regulation of transcription by Ultraviolet-B radiation in Arabidopsis thaliana. PhD thesis, University of Glasgow.

Abstract

Plants are sessile photo-autotrophic organisms and need to adapt constantly to a dynamic environment. Light is of utmost importance for plants to be able to monitor their surroundings. Ultraviolet-B radiation (UV-B; 280-315 nm) is an intrinsic part of sunlight and, depending on the wavelength and the fluence rate, it may be a stressful signal or an “informational” one. The so called photomorphogenic responses of plants to UV-B are largely mediated by the UV-B specific photoreceptor UV RESISTANCE LOCUS 8 (UVR8), which “senses” UV-B via a tryptophan based mechanism.
UVR8 is localised in the cytoplasm and the nucleus mainly as a homodimer. Upon UV-B irradiation it splits to its monomers and accumulates in the nucleus where it has been found to interact with the E3 Ubiquitin ligase COP1. In the nucleus UVR8 has been shown to associate with chromatin on loci of UV-B responsive genes, including that encoding for the bZIP transcription factor (TF) ELONGATED HYPOCOTYL 5 (HY5), a key effector of UVR8-dependent signalling pathways. The binding of UVR8 to chromatin appears to take place via interaction with histones (H2B in particular) rather than DNA itself. However, this association with chromatin seems not to be UV-B specific.
The above data suggest a mechanistic basis for an assumed function of UVR8 in the regulation transcription. It seems likely that UVR8 interacts with other proteins associated with chromatin to promote remodelling and/or recruits/activates TFs which in turn stimulate transcription of its target genes. The main objective of this study was to address the above working hypothesis.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Arabidopsis, photomorphogenesis, UV-B, transcription
• Subjects: Q Science > Q Science (General); Q Science > QH Natural history > QH301 Biology; Q Science > QK Botany
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Supervisor's Name: Jenkins, Professor Gareth
• Date of Award: 2015
• Depositing User: Christos Velanis
• Unique ID: glathesis:2015-6204
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 13 Mar 2015 09:55
• Last Modified: 13 Mar 2018 08:37
• URI: https://theses.gla.ac.uk/id/eprint/6204