ORCID ID

0000-0003-4114-2884

Publication Date

2021-05-13

Document Type

Doctoral Dissertation

Academic Program

Biochemistry and Molecular Pharmacology

Department

Biochemistry and Molecular Pharmacology

First Thesis Advisor

William E. Royer, PhD

Second Thesis Advisor

Celia A. Schiffer, PhD

Keywords

transcription factors, transcription co-activators, transcriptional regulation, macromolecular complexes, CtBPs, IRF3, CtBP-mediated repression complex, interferon-beta enhanceosome, CryoEM, homo-tetrameric complexes, cancer, infectious diseases

Abstract

Transcriptional deregulation has emerged as one of the leading causes in various human diseases. More than fifty percent of cancers arise due to frequent mutations in genes regulating transcription. Higher-order assembly via protein-protein interactions is one common mechanism of transcriptional regulation. Despite their critical role in regulating gene transcription and therapeutic relevance, detailed mechanistic understanding of these assemblies remains scarce. The primary focus of this thesis is to uncover important structural principles underlying the assembly and stability of multi-domain protein assemblies by characterizing components of the IFNβ enhanceosome and the CtBP-mediated repression complex.

Using a combination of biochemical and structural analyses, I showed that the transcriptional activator C-terminal binding protein 2 (CtBP2) is a tetramer by solving the 3.6Å cryoEM structure of CtBP2. I highlighted the types of interactions that stabilize the homo-tetramer and showed the relevance of the tetramer in CtBP2 transcriptional activity. Second, I used an integrative approach to investigate the structural features leading to activation of interferon regulator factor 3 (IRF3) and its interaction with DNA.

Although this work mostly focused on components of the CtBP2-mediated complex and IFNβ enhanceosome, the principles described here can be applied to other complexes. Therefore, these studies provide an overall understanding on how other macromolecular complexes regulate gene transcription. Furthermore, our structural-based analyses will provide a basis for designing drugs that can regulate gene transcription in cancer and immunological disorders.

DOI

10.13028/0v45-qd69

Rights and Permissions

Copyright is held by the author, with all rights reserved.

Available for download on Sunday, July 17, 2022

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