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Callie Lovejoy_Dissertation.pdf (4.31 MB)

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Role of Histone Acetyltransferase 1 in Maintenance of Genomic Integrity

Lovejoy, Callie
http://rave.ohiolink.edu/etdc/view?acc_num=osu1641394474986998

Abstract Details

2022, Doctor of Philosophy, Ohio State University, Molecular, Cellular and Developmental Biology.
Maintenance of genome stability and faithful transmission of genetic and epigenetic information comprises the foundation of cellular, and thus organismal fitness, within their environment. The greatest challenge to genome integrity is the process of genome duplication in preparation for cell division. This process is highly destructive to the genome’s epigenetic and 3D organization information, yet accurately rebuilt after DNA sequence copying. The dynamic nature of genome replication requires a vast number of proteins and complexes, one of which is Histone acetyltransferase 1 (HAT1). HAT1 is responsible for acetylating Histone H4 Lysines 5 and 12 in the cytoplasm before H3:H4 dimers are translocated to and imported into the nucleus and deposited on nascent chromatin during DNA replication. HAT1 loss in mice is neonatal lethal with pups exhibiting developmental lung defects and craniofacial defects. Mouse embryonic fibroblasts (MEFs) isolated from HAT1 -/- mice experience slowed growth, heightened sensitivity to DNA damage, and genome instability indicators such as chromosome breaks and fusions and changes in chromosome number. Recently, multiple lines of evidence suggest that histone acetyltransferase 1’s (HAT1) purpose extends far beyond its activity in new histone editing. In this study, we focus on HAT1’s role at replication forks and explore its possible role in promoting the nascent chromatin-nuclear periphery relationship. First, we developed a proximity-based Chromatin Assembly Assay (CAA) to study replication fork dynamics with standardized data collection and analysis procedures. We then used this protocol and HAT1 +/+ and HAT1 -/- immortalized Mouse Embryonic Fibroblasts (iMEFs) to investigate HAT1’s role in the maintenance of genomic integrity. We show that HAT1 transiently associates with nascent DNA and that loss of HAT1 slows replication fork progression, due at least in part to an increase in fork stalling. In addition, fork stalling stabilizes HAT1’s interaction with new DNA while loss of HAT1 at stalled forks leads to destabilization of the replication fork and MRE11-dependent degradation of nascent DNA. We also confirm a defect in CEP162 localization to nascent DNA in the absence of HAT1 and reduced accuracy of chromosome segregation. In the context of HAT1 and the nuclear periphery, we identify nuclear structure defects, specifically increased nuclear size and incidence of micronuclei and blebbing, in the absence of HAT1; a phenotype that mimics LMNB1 functional knockout models. We also observe a physical proximity of HAT1 with Lamin B1 and conclude that lamin-related defects in the absence of HAT1 must be functional in nature because expression and localization of Lamin B1 and Lamin AC are HAT1-independent. We also show that HAT1 influences the interaction of nascent chromatin with the nuclear periphery, possibly through epigenetic inheritance of H3K9me3.
Mark Parthun (Advisor)
Dmitri Kudryashov (Committee Member)
Kirk Mykytyn (Committee Member)
Jeff Parvin (Committee Member)
126 p.
Biology; Cellular Biology; Genetics; Molecular Biology
genome integrity; epigenetics; dna replication; hat1; nuclear lamina; inheritance

Recommended Citations

Citations

  • Lovejoy, C. (2022). Role of Histone Acetyltransferase 1 in Maintenance of Genomic Integrity [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1641394474986998

    APA Style (7th edition)

  • Lovejoy, Callie. Role of Histone Acetyltransferase 1 in Maintenance of Genomic Integrity. 2022. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1641394474986998.

    MLA Style (8th edition)

  • Lovejoy, Callie. "Role of Histone Acetyltransferase 1 in Maintenance of Genomic Integrity." Doctoral dissertation, Ohio State University, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=osu1641394474986998

    Chicago Manual of Style (17th edition)

osu1641394474986998
57
© 2022, some rights reserved.Creative Commons License Role of Histone Acetyltransferase 1 in Maintenance of Genomic Integrity by Callie Lovejoy is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.