Molecular Genetics Commons^™

Computational Insights Into Nucleosome Dynamics In Epigenetics Using Molecular Dynamics Simulations, Rutika Patel

Dissertations, Theses, and Capstone Projects

Nucleosome core particles (NCP) are the building blocks that form a highly organized and compact chromatin structure. Nucleosomes package DNA in the nucleus of eukaryotic cells. The NCP consists of about 147 base pairs of DNA wrapped around the histone octamer, with 1.65 superhelical turns in a left-handed manner. The histone octamer is composed of two copies of H3, H4, H2A, and H2B. Together with histone H1 and linker DNA, they further assemble into a higher-order chromatin structure. The nucleosome complex is stabilized by electrostatic interactions between positively charged histone residues and the negatively charged DNA backbone. To effectively access …

Determining Genes Involved In Recovery From Chemotherapy In 4t1, Emt6, And Eo771 Breast Cancer Cells, Akash Jagdeesh, Joseph Landry Ph.D.

Undergraduate Research Posters

Breast cancer is one of the most common types of cancer, and often has poor prognosis. Traditional treatments for breast cancer include chemotherapy, which involves a chemical attack on all growing cells within the body. However, these treatments are not 100% effective, and patients might experience recurrence in their cancer months or years after achieving remission. Cancer cells can evade chemotherapy through five mechanisms: senescence, quiescence, cytoprotective autophagy, and apoptosis/necroptosis suppression. Prior studies have conducted CRISPR screens and experiments involving inhibition of epigenetic regulators, to alter the regulation of genes that can contribute to breast cancer chemotherapy resistance. This study …

Regulation Of Chromatin Remodeling By The Post-Hsa Domain Of Brg1, A Subunit The Baf Atp-Dependent Chromatin Remodeling Complex, Min Sze Ewe

Theses & Dissertations

The ATP-dependent chromatin remodeler BAF complex regulates nucleosome positioning, chromatin accessibility, and tissue specific gene expression. Its catalytic subunit, BRG1, contains several regulatory domains including the post-HSA region, proposed to modulate ATPase activity. Multiple cancer-associated mutations map to these regulatory regions underscoring their importance, yet the precise role of the post-HSA region in chromatin remodeling remains poorly understood.

To investigate the function of the post-HSA domain, we ectopically expressed FLAG-tagged BRG1 with post-HSA deletion (Δpost-HSA BRG1) in mouse embryonic stem cells. Western blot analysis confirmed expression of the mutant protein. To determine the effects of mutant protein expression on chromatin …

Exploring Variability Of The Cg18562578 Methylquant Assay For The Forensic Discrimination Of Monozygotic Twins, Sydney E. Arnold

Student Theses

Monozygotic (MZ) twins possess identical DNA sequences, posing a problem for forensic scientists, as they are incapable of distinguishing MZ twins from each other using traditional DNA identification methods. However, the epigenomes of MZ twins will differ and might be used for their forensic discrimination. Here, we explored the variability of an assay previously developed by our laboratory that showed high discrimination potential for MZ twins using buccal swab DNA, cg18562578 MethylQuant. We measured precision at each step: bisulfite conversion, nested PCR, and qPCR, reproducibility, and repeatability. DNA methylation ratios were compared between two analysts carrying each step using the …

Examining Loss Of Imprint In F1 Hybrid Female Mice Due To X Chromosome Epimutation And The Implications For Autism, Arianna H. Roach

Honors Scholar Theses

Sex biases are prevalent among various neurodevelopmental disorders, with males experiencing them at higher frequencies or severities than females. This male bias is poorly understood, and our lab aims to elucidate this mechanism using our model of transgenerational epigenetic inheritance. Our lab identified the cluster of genes Xlr3b/4b/4c on the X chromosome that are imprinted in the female brain. Preliminary studies suggest that Xlr3 acts as a mediator molecule in our model. Xlr3 knockdown male mice exhibited significant meiocyte loss that can be attributed to Meiotic Sex Chromosome Inactivation. Their female offspring also displayed loss of imprinting of Xlr3 and …

A Study To Identify The Causal Rare Genetic Variants In Primary Open And Closed Angle Glaucoma, Pseudoexfoliation Syndrome, And Associated Glaucoma, Suganya K

Theses and Dissertations

BACKGROUND: Glaucoma is the second most common cause of blindness globally typically diagnosed with a triad of clinical symptoms of increased intraocular pressure (IOP) with associated optic disc, optic nerve head (ONH) changes, and visual field defects. Genetic and environmental factors are some of the strong aetiology factors for glaucoma and identification of these factors has a potential implication in the management of the disease and its outcome. There is a paradigm shift towards understanding the genetics of glaucoma, wherein the variants in the nuclear, mitochondrial genome and other regulatory regions are being identified as contributing risk factors.

METHODOLOGY AND …

Early Onset Alzheimer’S Disease Markers In Mouse Hippocampus Unveiled By Single-Cell Transcriptomic Analysis Following Cranial Radiotherapy, Tuba Aksoy

Dissertations and Theses (Open Access)

Cranial radiation therapy plays an integral role in the treatment of brain tumors but can lead to progressive cognitive deficits in survivors by mechanisms that are poorly understood. To develop preventive or mitigative strategies, it is crucial to better understand the underlying pathogenesis of radiation-induced cognitive impairments. The study investigated single-cell transcriptomics and DNA methylation changes as potential drivers of persistent cellular dysfunction after radiation exposure, specifically concentrating on the CA1-3 regions of the hippocampus and the prefrontal cortex due to their role in cognitive functions. Thirteen-week-old mice underwent whole-brain radiation at clinically relevant doses. Following whole-brain radiation, an assessment …

Re-Programming Transcription Factor Function For Neuroscience Research Of Addiction: Investigating The Role Of Zinc Finger Proteins In Driving Cocaine Reinforcement In Mice, Joseph A. Picone

Theses and Dissertations

Administration of addictive drugs like cocaine or morphine initiates aberrant gene transcription within brain reward circuitry neurons, which contributes to the lasting behavioral maladaptations that define addiction. The drug-induced expression and function of key brain transcription factors (TFs) is one major mechanism through which these drugs are able to regulate transcription, and as a consequence, lasting damaging drug-related behaviors including compulsive drug use. The goal of this dissertation is to more fully understand the molecular mechanistic drug-specific actions of TFs within the rodent nucleus accumbens (NAc). The findings from these studies could serve as the basis to identify novel candidate …

Epigenetic Mechanism Of Ebp1 In Nlrp-Dependent Development, Summer Reign Moore

Graduate Theses/Dissertations

ErbB3-binding protein 1 (EBP1) helps regulate gene expression through various epigenetic modifications and is crucial for embryotic development. NLRP2 and NLRP7 are more commonly known for their roles in the immune system, however, recent research has implicated NLRP2 and 7 as critical factors in embryonic development. EPB1, NLRP2, and NLRP7 dysfunction is a known cause of recurrent miscarriages and other developmental diseases, including infertility. NLRP2 and NLRP7 are also known to affect the levels of DNA methylation, despite that they are located exclusively in the cytoplasm. However, EBP1 can be located in the nucleus and cytoplasm, and is known to …

A Study Of The Snd1/Prmt5 Axis In Liver Cancer By Genetic Mouse Models, Tanner Wright, Tanner Wright

Dissertations and Theses (Open Access)

Arginine methylation is an essential post-translational modification (PTM) in cells. Protein arginine methyltransferase 5 (PRMT5) is the primary enzyme that catalyzes symmetric dimethyl arginine (SDMA) and requires methylosome protein 50 (MEP50) for stability and enzymatic activity which are necessary for life and development. Effector proteins bind different types of PTM’s to facilitate signaling. Staphylococcal nuclease Tudor domain containing 1 (SND1) is an effector that specifically binds SDMA via its single C-terminal Tudor domain. Both SND1 and PRMT5 have been implicated in hepatocellular carcinoma (HCC). SND1 has been confirmed as a driver of HCC using genetically engineered mouse models (GEMMs), though, …

Molecular Mechanisms Behind Sars-Cov-2 Induced Host Genome Restructuring, Erin Simpson

Dissertations and Theses (Open Access)

Severe Acute Respiratory Syndrome Coronavirus -2 (SARS-CoV-2) has caused unprecedented morbidity and mortality worldwide. There are two pathophysiological hallmarks associated with severe patient outcomes after SARS-CoV-2 acute infection, namely delayed/weakened interferon production and overactive inflammatory responses. Our previous work has shown that these altered immune responses are due, at least in part, to significant alterations in 3D genome organization and epigenetic landscape following SARS-CoV-2 infection that are distinct from and more severe than changes caused by other viral infections or immune stimulants. While these changes at the chromatin level are important for understanding the immune dysregulation seen in some cases …

Dna Methylation And The Response To Infection In Introduced House Sparrows, Melanie Gibson

College of Graduate Studies: Theses & Dissertations

Epigenetics is the study of molecular modification of a genome without changing its base pairs. The most studied type of epigenetic mechanism is DNA methylation, which is capable of turning a gene “on” or “off.” Epigenetic potential is the capacity to which an individual can have methylation on its genome. The more CpGs available, the greater the epigenetic potential. In invasive species, genetic variation has been observed to be paradoxical: not much of it exists on a genomic level, but epigenetically, phenotypic variation can occur. The focus on shift in gene expression in this study is on Toll-Like Receptor 4 …

Discrimination Of Monozygotic Twins Using Dna Methylation Levels Of One Cpg Site At Chromosome 3, Dino O. Robinson

Student Theses

Conventional STR typing, commonly used in forensics for human identification, poses a problem in criminal cases and paternity disputes involving monozygotic (MZ) twins because they share identical DNA sequences. To date, no routine method is available in forensics to differentiate between individuals of MZ pairs. Recently, epigenetic methods measuring differential DNA methylation patterns have been applied to MZ twin differentiation. In this study, we investigated the potential to identify MZ twins using a previously identified DNA methylation site in chromosome 3, cg18562578, in a sample of 129 MZ and 37 dizygotic (DZ) twin pairs. We used bisulfite converted saliva DNA …

The Functional Importance Of Methyl Cpg Binding Domain Proteins 2 And 3 In Regulating Fetal Hemoglobin Expression In Human Adult Erythroid Cells, Alexander Azzo

Theses and Dissertations

Humans undergo two developmental switches in the predominantly expressed β-like globin chain during embryogenesis and fetal development. The first switch from embryonic (ε) to fetal (γ) occurs around week 5 of embryonic development, while the second switch from fetal to adult (β) globin occurs shortly after birth. By adulthood, fetal hemoglobin represents only 1-2% of total hemoglobin in the blood. As sufficiently elevated levels of fetal hemoglobin are beneficial for improving clinical outcomes in sickle cell disease and β-thalassemia, the mechanisms that enforce silencing of fetal hemoglobin expression postnatally are of great clinical significance. The methyl-CpG binding domain protein MBD2 …

Dna Methylation By Restriction Modification Systems Affects The Global Transcriptome Profile In Borrelia Burgdorferi, Timothey Casselli, Yvonne Tourand, Adam Scheidegger, William K. Arnold, Anna Proulx, Brian Stevenson, Catherine A. Brissette

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Prokaryote restriction modification (RM) systems serve to protect bacteria from potentially detrimental foreign DNA. Recent evidence suggests that DNA methylation by the methyltransferase (MTase) components of RM systems can also have effects on transcriptome profiles. The type strain of the causative agent of Lyme disease, Borrelia burgdorferi B31, possesses two RM systems with N6-methyladenosine (m6A) MTase activity, which are encoded by the bbe02 gene located on linear plasmid lp25 and bbq67 on lp56. The specific recognition and/or methylation sequences had not been identified for either of these B. burgdorferi MTases, and it was not previously known whether these RM …

Characterizing Epigenetic Regulation In The Developing Chicken Retina, Bejan Abbas Rasoul

Masters Theses, 2010-2019

The retina, the sensory neuronal tissue within the eye, is composed of three layers of neuronal cells connected by two synaptic layers lining the inside of the anterior portion of the eye. Multipotent retinal precursor cells are genetically homogeneous and differentiate into mature retinal neurons due to differential gene expression. Differences in gene expression have been correlated with epigenetic modifications such as DNA methylation. DNA methylation of upstream regulatory elements is associated with transcriptional silencing of gene expression. Years of research in retinal development has identified the numerous genes expressed during the main steps of retinal development, however, it is …

The Regulation Of Dna Methylation In Mammalian Development And Cancer, Nicolas Veland

Dissertations and Theses (Open Access)

DNA methylation is an essential epigenetic modification in mammals, as it plays important regulatory roles in multiple biological processes, such as gene transcription, maintenance of chromosomal structure and genomic stability, genomic imprinting, retrotransposon silencing, and X-chromosome inactivation. Dysregulation of DNA methylation is associated with various human diseases. For example, cancer cells usually show global hypomethylation and regional hypermenthylation, which have been implicated in genomic instability and tumor suppressor silencing, respectively. Although great progress has been made in elucidating the biological functions of DNA methylation over the last several decades, how DNA methylation patterns and levels are regulated and dysregulated is …

The Effects Of Forest Degradation On Dna Methylation In Central African Songbirds, Andrew K. Wiegardt

Cal Poly Humboldt theses and projects

Environmentally-induced stress can initiate a molecular response through DNA methylation, which can alter gene expression, thereby serving as a mechanism allowing individuals to acclimate to a changing environment within their lifetime. In addition to DNA methylation, the production and release of corticosterone is a physiological mechanism by which birds can cope with acute environmental stressors. To assess how environmental stress impacted DNA methylation and corticosterone, I collected blood and feather samples from three understory avian species (Alethe castanea, Bleda notatus and Pseudalethe poliocephala), along a disturbance gradient in the lowland Guinean rainforest adjacent to the village of …

Epigenetics Of Host-Pathogen Interactions: The Effect Of Acetosyringone On Ti Plasmid Methylation Patterns In Agrobacterium Tumefaciens C58, Genevieve Roberts

Honors Projects

The plant pathogen Agrobacterium tumefaciens C58 can transfer a portion of its tumor-inducing (Ti) plasmid to plant hosts in response to the plant wound signals, including Acetosyringone. The portion transferred is aptly titled Transfer DNA (T-DNA) which encode genes involved in tumor production and biosynthesis of a unique bacterial food source called opines that provide an advantage to the inducing Agrobacterium. The Ti plasmid contains a number of genes, including the virulence region that enables T-DNA transfer. Epigenetics investigates how chemical modifications to DNA that don’t alter sequence are used to control gene expression (for example, genes involved in pathogen …

Chromatin-Modifying Agents Convert Fibroblasts To Oct4+ And Vegfr-2+ Capillary Tube-Forming Cells, Anita Wary, Neil Wary '18, Jugajyoti Baruah, Victoria Mastej, Kishore K. Wary

Student Publications & Research

Rationale
The human epigenome is plastic. The goal of this study was to address if fibroblast cells can be epigenetically modified to promote neovessel formation.

Methods and results
Here, we used highly abundant human adult dermal fibroblast cells (hADFCs) that were treated with the chromatin-modifying agents 5-aza-2'-deoxycytidine and trichostatin A, and subsequently subjected to differentiation by activating Wnt signaling. Our results show that these epigenetically modified hADFCs increasingly expressed β-catenin, pluripotency factor octamer-binding transcription factor-4 (OCT4, also known as POU5F1), and endothelial cell (EC) marker called vascular endothelial growth factor receptor-2 (VEGFR-2, also known as Fetal Liver Kinase-1). In microscopic …

Targeted Germ Cell Knockdown Of Xlr3 In Mus Musculus, Caity Miller

Honors Scholar Theses

The X chromosome is rather distinct from autosomes due to the unique regulatory and functional characteristics it exhibits. Xlr3 is just one gene in a superfamily of highly related, and homologous genes found on the X chromosome in mice. Xlr3 is part of a complex, imprinted locus, of which the function is not well understood, although its protein product can be found in testis and oocyte. However, it is theorized that the region may be implicated in the progression of meiosis, due to localization of XLR3. This study sought to characterize the function of Xlr3 through the use of a …

Epigenetic Editing To Validate Findings From Methylome-Wide Association Studies Of Neuropsychiatric Disorders, Robin F. Chan

Theses and Dissertations

DNA methylation is necessary for learning, memory consolidation and has been implicated in a number of neuropsychiatric disorders. Obtaining high quality and comprehensive data for the three common forms of methylation in brain is challenging for methylome-wide association studies (MWAS). To address this we optimized a panel of enrichment methods for screening the brain methylome. Results show that these enrichment techniques approach the coverage and fidelity of the current gold standard bisulfite based techniques. Our MBD-based method can also be used with low amounts of genomic material from limited human biomaterials. Psychiatric disorders have high prevalence and are often chronic …

Epigenetic Characterization Of Human Retina Cells, Nicholas R. Dunham

Senior Honors Projects, 2010-2019

DNA methylation is an epigenetic modifier that modulates gene expression in plant and vertebrate genomes. The aim of this study was to characterize the role of DNA methylation in the human retina, particularly within rod and cone photoreceptor retinal neurons. Previous studies investigating DNA methylation in murine retinal cells and retina-derived human retinoblastoma immortalized cell culture lines demonstrate an inverse relationship between DNA methylation and transcriptional activity. Here, we used gene-specific bisulfite pyrosequencing analysis to measure DNA methylation in the genomes of human ocular cells in an effort to characterize the role of this important epigenetic modifier. These results can …

Gene Expression Profiling In An Alzheimer's Disease Mouse Model, Matthew R. Dalton

Senior Honors Theses

Explaining precisely how Alzheimer’s disease (AD)—the world’s most common form of dementia—materializes in the human brain has proven to be one of the most elusive ends in modern medicine. Progressive memory loss, neurodegeneration, and the presence of abnormal protein aggregates of amyloid-beta (Aβ) and neurofibrillary tangles (NFT) characterize this disease. Genome sequencing provides researchers with the ability to better identify disease-related changes in gene expression, some of which may play a role in the initiation and progression toward the AD-like state. Intimate interactions between tissues have been observed in many diseases, particularly between the brain and blood. This analysis seeks …

Epacs: Epigenetic Regulators That Affect Cell Survival In Cancer., Catherine Murari

Theses & Dissertations

Cyclic adenosine monophosphate (cAMP) is a second messenger responsive to many external stimuli, playing an important role in cellular gene expression, metabolism, migration, differentiation, hypertrophy, apoptosis and secretion. All of these cellular functions are important in many diseases including cancer. Most of its effects were initially attributed to the classical protein kinase A (PKA) protein, but cellular functions such as proliferation and migration were found to be PKA independent and dependent on the newly discovered exchange proteins directly activated by cAMP (EPACs). EPACs are single polypeptides that primarily function as guanine exchange factors (GEFs) for Rap proteins that allow the …

Environmental Stimuli And Intragenerational Epigenetics, Nicholas J. Napier

Student Scholarship

Epigenetics is the study of any change in gene expression that is not mediated by DNA sequence. The effects of environmental stimuli on epigenetic changes have been studied extensively in recent years. Multiple reviews have provided comprehensive summations of the effects of environmental stimuli on transgenerational epigenetic changes, but few reviews have focused upon environment-induced intragenerational epigenetic changes. This review will summarize current knowledge of the intragenerational epigenetic changes that are induced by two groups of well-studied environmental stimuli: nutritional deficiencies and carcinogens. This survey of intragenerational epigenetic changes will focus upon the mechanisms behind them, the disorders associated with …

Structural And Functional Characterization Of The Mbd2-Nurd Co-Repressor Complex, Megha Desai

Theses and Dissertations

The MBD2-NuRD co-repressor complex is an epigenetic regulator of the developmental silencing of embryonic and fetal β-type globin genes in adult erythroid cells as well as aberrant methylation-dependent silencing of tumor suppressor genes in neoplastic diseases. Biochemical characterization of the MBD2-NuRD complex in chicken erythroid cells identified RbAp46/48, HDAC1/2, MTA1/2/3, p66α/β, Mi2α/β and MBD2 to comprise this multi-protein complex.

In the work presented in Chapter 2, we have pursued biophysical and molecular studies to describe a previously uncharacterized domain of human MBD2 (MBD2_IDR). Biophysical analyses show that MBD2_IDR is an intrinsically disordered region (IDR). Despite this inherent …

Contributions Of Apolipoprotein E And Environmental Factors In Alzheimer’S Disease, Kelly C. Mcmullen

Senior Honors Theses

Alzheimer’s disease (AD) is a debilitating neurodegenerative disorder, which currently affects nearly 5.5 million people in the United States alone. Clinical features often exhibited in AD include memory loss, unusual behavior, personality changes, and impaired cognitive function. The primary molecular hallmarks of AD include deposits of senile plaques and neurofibrillary tangles in brain tissue. A myriad of risk factors are associated with the disease, but this review will focus on Apolipoprotein E polymorphisms and certain environmental factors. Understanding the role of Apolipoprotein E in AD pathology may aid in the development of certain drug therapies and possible cures for AD. …

Examination Of The Chromatin Structure Of Xlr3b Using The Chromosome Conformation Capture Assay, Sarah Elise Conderino

Honors Scholar Theses

Imprinted genes contain epigenetic modifications that influence expression patterns based on parent-of-origin. Recent studies have shown that imprinted genes contribute to numerous human diseases and disorders. Xlr3b, an imprinted gene on the X chromosome, has been implicated in social and behavioral deficits characteristic of disorders such as Turner syndrome and autism. The imprinting mechanism of this gene is still unknown, and this study analyzed the native chromatin structure of Xlr3b through the chromosome conformation capture assay to determine if there are any long-range interactions that regulate the expression of this gene. Brain tissue from a mouse model of Turner …