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Title: The role of high mobility group of nucleosome binding proteins in stem cell biology and differentiation
Author: Garza Manero, Sylvia Patricia
ISNI:       0000 0004 7655 5192
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 2019
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The high mobility group of nucleosome binding proteins (HMGNs) are chromatin architectural proteins that bind specifically to nucleosomes and influence chromatin structure and DNA-dependent functions. However, the mechanisms underlying these events remain largely unknown. HMGN1 and HMGN2 are highly expressed by embryonic stem cells and are downregulated as differentiation proceeds. Nevertheless, embryonic and adult neural stem cells retain elevated levels of these proteins. Chromatin plasticity is essential for the pluri- and multipotency of stem cells and it is achieved by maintaining an open and dynamic chromatin conformation. Conversely, developmental potential seems to be restricted by chromatin condensation. The present work shows that loss of HMGN1 or HMGN2 in pluripotent embryonal carcinoma cells leads to increased spontaneous neuronal differentiation, which is accompanied by a reduction in pluripotency markers and higher gene expression of lineage-specific transcription factors. Inhibition of signalling pathways relevant for neurogenesis does not re-establish the phenotype observed in Hmgn2-knockout cells. Withdrawal of the factors sustaining pluripotency in embryonal carcinoma cells results in higher induction of pro-neural factors in cells lacking HMGN1 or HMGN2. Neural stem cells derived from Hmgn-knockout cells also display higher gene expression of pro-neural transcription factors and increased spontaneous neuronal differentiation. Loss of HMGN2 disrupts the active histone modification landscape, and therefore affects the chromatin structure at local and global levels. The proposition is that the local changes directly influence the transcription rates of pluripotency and lineage-specific transcription factors, while the global changes may restrict chromatin plasticity. The present data support a hypothesis whereby HMGNs contribute to the chromatin plasticity of stem cells by promoting an active histone modification landscape and open chromatin conformation, which are essential for preserving the self-renewal and developmental potential of stem cells.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
Keywords: QD Chemistry ; QP Physiology