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Title: Mechanisms regulating the imprinted tumour suppressor gene DIRAS3 in normal development and cancer
Author: Huddleston, J. E.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2010
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In this thesis I have extended previous work on DNA methylation of DIRAS3 using quantitative methods and studied a broad range of tissues. This leads to identification of a probable germline DMR. I have identified CTCF and cohesion binding sites in the DIRAS3 locus and shown that these factors positively regulate DIRAS3 expression. Methylation changes in cancer at DIRAS3 prevents CTCF binding leading to silencing of DIRAS3. This silencing can be reversed using demethylating agents. I have identified putative enhancer regions by their chromatin signature and tested them for enhancer activity using luciferase assays. I have proposed models for regulation of DIRAS3 via allele specific higher order chromatin structures mediated by CTCF/cohesion. I have identified a long non-coding RNA that is associated with the DIRAS3region. The long non-coding RNA is not a ‘classical’ imprinted gene as the promoter is unmethylated, however the genomic organisation of the long non-coding RNA relative to DIRAS3 bears some similarities to the imprinted retrogenes. The non-coding RNA is alternatively spliced, and some splice variants are imprinted and maternally expressed. This may represent a novel mechanism by which an imprinted gene can affect splicing patterns of an associated gene. I hypothesised that the non-coding RNA might have a role in setting up maternal methylation imprints at DIRAS3 and made a mouse model to test the role of transcription through the DIRAS3 DMRs in the germline.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available