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The role and mechanisms of action of PMLII on regulating gene expression
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Martucci, Sophie Marie (2020) The role and mechanisms of action of PMLII on regulating gene expression. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b3598161~S15
Abstract
The promyelocytic leukaemia protein (PML) has seven splice variants expressed in humans enabling this protein to conduct numerous biological functions ranging from tumour suppression, antiviral responses to transcriptional regulation. This study focuses on the PML isoform II (PMLII) and its role in regulating transcription of genes involved in the immune response upon viral infection.
The PMLII protein is an important PML isoform found within small nuclear structures called PML-nuclear bodies (PML-NBs) and is involved with many cellular processes. PMLII is a key element of the immune response to viral infections, interacting with numerous components in signalling pathways associated with type I and II interferon (IFN) responses, including transcription factors such as NFκB and STAT1. It has been shown that PMLII is vital for regulating gene expression and for efficient induction of IFN stimulated genes (ISGs) during responses to viral infections. This function is brought about through PMLII interacting with many proteins, such as CREB binding protein (CBP), assisting with transcriptional complex assembly, and functions to change the chromatin landscape by moderating chromatin remodelling enzymes, including the SWItch/Sucrose Non-fermentable (SWI/SNF) complex and histone chaperone proteins, such as Death Domain Associated Protein (DAXX).
Through the use of chromatin immunoprecipitation-qPCR studies, the extent to which PMLII was involved in changing histone markers present upon the chromatin of the IFNβ gene and ISG54 was investigated. Genome-wide ATAC sequencing analysis was also conducted to identify PMLII-depended changes in chromatin openness that occurred under both IFN-stimulated and basal conditions. Co-immunoprecipitation experiments were also performed to investigate interactions between PMLII and proteins involved in regulating transcription and chromatin structure.
The results from these experiments indicated an involvement of PMLII in regulating the histone markers on the IFNβ and ISG54 genes, with changes in both markers of transcriptional activity and inactivity potentially altered by the absence of PMLII. The ATAC sequencing analysis showed a clear role for PMLII in determining chromatin openness both at rest and upon IFN stimulation, with numerous significantly different regions of chromatin identified upon removal of PMLII. Comparative analysis of chromatin from each condition was used to identify different temporal patterns whereby genes activated by IFN varied in their rate of inactivation, but also showed different enriched motifs and GO terms within each distinct temporal group.
The enriched motifs found within these analyses define the factors through which PMLII is eliciting its changes to the chromatin and regulating gene transcription. These changes confirmed the involvement of PMLII in the innate immune response, but also implied involvement of PMLII with the nervous system and other pathways. However, the exact mechanism by which PMLII is connected to each motif and its mechanism of action is not yet fully characterised. Further research into pathways highlighted by this work involving PMLII interacting with various proteins will better improve our understanding of this multifaceted protein. As PMLII is important in ensuring appropriate immunological signalling and regulates gene expression, alterations in these processes are linked with many pathologies including autoimmunity, arthritis and cancers. By better understanding how PMLII functions, novel therapies could be developed for these immunological diseases.
Item Type: | Thesis (PhD) | ||||
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Subjects: | Q Science > QH Natural history > QH301 Biology Q Science > QH Natural history > QH426 Genetics |
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Library of Congress Subject Headings (LCSH): | Tumor suppressor proteins, Genetic transcription -- Regulation, Gene expression | ||||
Official Date: | October 2020 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | School of Life Sciences | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Leppard, K. N. (Keith N.) ; Ott, Sascha | ||||
Sponsors: | Biotechnology and Biological Sciences Research Council (Great Britain) | ||||
Format of File: | |||||
Extent: | xvii, 293 leaves : colour illustrations | ||||
Language: | eng |
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