Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598423
Title: JAK-STAT signalling at chromatin
Author: Dawson, M. A. F.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2010
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Abstract:
The aim of my work was to explore the possibility that the mammalian JAK2 signalling pathway influences the structure and function of chromatin. I have demonstrated that JAK2 is present in the nucleus of both human haematopoietic cell lines and primary cells. My results suggest that JAK2 functions as a histone tyrosine kinase and phosphorylates histone H3 at tyrosine-41 (H3Y41). This novel histone modification, the first described tyrosine phosphorylation on any of the non-variant histones, regulates the binding of heterochromatin protein 1-alpha (HP1α) at a new binding site on chromatin. HP1α uses its chromo-shadow domain to bind the H3Y41 region. Phosphorylation of H3Y41 by JAK2 reduces its affinity for chromatin. This reciprocal relationship was given a functional context by demonstrating its relationship to the expression of a key haematopoietic oncogene Imo2. Genome-wide studies demonstrate that H3Y41ph is present at the 5’ end of genes and is highly correlated with active transcription. This is the first comprehensive genome wide mapping of a histone phosphorylation mark and potentially highlights a role for this novel modification in the regulation of transcription. H3Y41ph was also present at specific cis-regulatory elements on JAK2-STAT5 target genes and genome-wide mapping of STAT5 binding confirmed that STAT5 binding and H3Y41ph was coincident at a significant number of sites within the human genome. This interesting observation suggests that canonical JAK2-STAT5 signalling is not confined to the cytoplasma but also occurs at chromatin. These findings extend the existing paradigm of JAK-STAT signalling and provide a platform for a better understanding of this critical signalling pathway, which is important in both normal development and oncogenesis.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.598423  DOI: Not available
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