Date of Award

Spring 5-2021

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Molecular Science and Nanotechnology

First Advisor

Jamie Newman

Abstract

Selective gene expression is crucial in maintaining the self-renewing and multipotent properties of stem cells. Mediator is a large, evolutionarily conserved, multisubunit protein complex that modulates gene expression by relaying signals from cell type-specific transcription factors to RNA polymerase II. In humans, this complex consists of 30 subunits arranged in four modules: head, middle, tail, and kinase. In our introduction, we show the state of the field of Mediator study with a focus on the critical kinase module. In the following chapters, we used siRNA knockdowns to investigate the roles of the highly-conserved core subunit MED31 and the kinase module subunit MED12 in directing cell state in human adult-derived mesenchymal stem cells harvested from either bone marrow or adipose tissue. Knockdown of MED31 resulted in a decrease in self-renewal based on cell assays and monitoring of gene expression and lipid vesicle formation. MED12 knockdown has produced similar results, but a potential interaction between MED12 and the master regulator of adipogenesis, PPARG, has been revealed through the application of delayed knockdown assays. These studies seek to expand our current understanding of stem cell behavior and how it relates to the critical Mediator complex in order to further progress toward stem cell therapies. In our final chapter, we show bioinformatics techniques that are rapidly transforming the field of biology that will also greatly impact the study of the Mediator complex in human stem cells.

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