All ETDs from UAB

Advisory Committee Chair

Tim M Townes

Advisory Committee Members

Chenbai Chang

Christopher A Klug

Hengbin Wang

Thomas M Ryan

Document Type

Dissertation

Date of Award

2011

Degree Name by School

Doctor of Philosophy (PhD) Heersink School of Medicine

Abstract

Embryonic stem cells (ESCs) were first derived from the inner cell mass (ICM) of blastocyst-stage embryos. ESCs are distinguished from other cell types by their pluripotency and unlimited self-replication. ESCs are able to differentiate into multiple cell types that represent all three primary germ layers (ectoderm, mesoderm and endoderm) and can form an entire adult organism. Under defined conditions, ESCs are self-renewable and have an extended life-span without compromising pluripotency. The plasticity of ESCs provides opportunities for regenerative medicine. The recent production of induced pluripotent stem cells (iPSC) offers an ideal "personalized" substitute for ESCs. Overexpression of four transcription factors, Oct4, Sox2 , Klf4 and c-Myc can reprogram mouse somatic fibroblasts to iPSCs which are similar to ESCs in many biological properties including gene expression patterns, DNA methylation status and the differentiation ability. I demonstrate an advanced protocol for iPSC reprogramming. By using single lentiviral-based vector combined with Cre-loxP system, I established transgene- free iPSC lines from adult mouse fibroblasts. Dissecting the mechanisms that control transcription of pluripotency core factors is critical for understanding the mechanisms that induce and maintain pluripotency. I propose a novel mechanism in which FGF signaling fine-tunes Sox2 activity through post-translational modification of a critical interacting protein, Parp1, and balances the maintenance of ESC pluripotency and differentiation. In addition, I demonstrated that regulation of Sox2 activity by Parp1 is critical for efficient generation of induced pluripotent stem cells (iPSCs).

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