Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.582377
Title: Transcription factor interactions at the promoter of the Arabidopsis circadian clock gene LHY
Author: Davies, Siân Elizabeth Wynne
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2013
Availability of Full Text:
Access through EThOS:
Access through Institution:
Abstract:
The circadian clock is the endogenous mechanism by which a wide variety of biological processes are regulated in anticipation of daily changes in the external environment. In Arabidopsis thaliana, the clock comprises a number of complex gene and protein interactions, involving multiple regulatory feedback loops. The clock gene LHY has a central role in these loops, activating and repressing morning- and evening- expressed genes respectively. These clock genes in turn sequentially repress the expression of LHY throughout the day and night, restricting it to a sharp transcriptional peak at dawn. However, the molecular mechanisms of these regulatory interactions with the LHY promoter were not known. Therefore, this project first aimed to determine which promoter motifs are responsible for mediating regulation of LHY circadian expression. This was achieved through luciferase assays with mutated pLHY:LUC reporter constructs, which identified the CT-rich region as responsible for rhythmic expression of LHY, and the G-box as mediating regulation by the clock protein TOC1. Since few regulators were known to target the LHY promoter, this project also aimed to identify transcription factors binding the promoter using a Yeast One-Hybrid assay. Transcription factors with roles in a wide variety of biological pathways were identified from this screen, with abiotic stress and plant defence pathways particularly well-represented. In addition, a number of antagonistic and synergistic regulatory interactions were established as occurring between stress factors and clock proteins at specific promoter motifs. We can therefore conclude that LHY is regulated by a complex network of transcription factor interactions, enabling the rapid integration of environmental stress signals into the clock.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.582377  DOI: Not available
Keywords: QH301 Biology ; QH426 Genetics
Share: