Genetics and Genomics Commons^™

Npsd4: A New Player In Sumo-Dependent Dna Repair, Erin Atkinson

Dissertations and Theses (Open Access)

The human genome is under constant threat from sources of damage and stress. Improper resolution of DNA damage lesions can lead to mutations, oncogene activation, and genomic instability. Difficult-to-replicate-loci present barriers to DNA replication that, when not properly resolved, lead to replication fork stalling and collapse and genomic instability.

DNA damage and replication stress trigger signaling cascades potentiated by multiple types of post-translational modifications, including SUMOylation. Through proteomic analysis of proteins involved in SUMOylation following DNA damage, our lab identified an uncharacterized protein that we named New Player in SUMO-dependent DNA damage repair 4 (NPSD4). Through an additional proteomic screen, …

Unveiling Global Roles Of G-Quadruplexes And G4-22 In Human Genetics, Ruth Barros De Paula

Dissertations and Theses (Open Access)

G-quadruplexes are non-B DNA structures formed by four or more runs of repeated guanines that confer unique features to living organism’s genomes. These sequences are enriched in regulatory regions, such as promoters and 5’ UTRs, and have distinct regulatory roles in both health and disease states. Even though previous studies showed the impact of G4 in gene expression, none of them summarized the location-specific effect of G4. Also, there is no broad understanding about the most common G4 repeat in the human genome, named here as G4-22, and how it links to the evolution of mammals and their biology. In …

Understanding The Pathogenesis Of Renal Medullary Carcinoma, Melinda Soeung

Dissertations and Theses (Open Access)

Renal medullary carcinoma (RMC) is a lethal cancer that predominantly affects young individuals with sickle cell trait (SCT). It is not currently understood why RMC only affects certain individuals with SCT. We found that patients with RMC more frequently participated in high-intensity exercise than matched controls. Using mouse models of SCT, we demonstrated the significant increase of renal hypoxia in the right kidney following high- but not moderate-intensity exercise. We also demonstrated in cell culture studies that SMARCB1 is ubiquitinated for proteasome-mediated degradation in hypoxia, and the re-expression of SMARCB1 leads to compromised proliferation in renal cells specifically in the …

Understanding The Role Of Arglu1 In Interferon Signaling Activation In Breast Cancer, Phuoc Nguyen

Dissertations and Theses (Open Access)

In the U.S., the highest number of new cancer cases belongs to breast cancer in women, and this cancer also bears the second-highest death rate in women. Despite significant progress in breast cancer treatment that has been made in the past several decades, innovative and efficient therapies are still needed to eradicate this deadly disease. Novel cancer immunotherapy with immune checkpoint blockade (ICB) could induce long-lasting responses and improve survival in hard-to-treat malignancies. Regrettably, only a fraction of breast cancer patients respond to this highly promising strategy. To improving ICB therapy in breast cancer treatment, IFN signaling induction is a …

Regulation Of Lung Mesenchymal Cells By Epithelial Wnt Ligands, Odemaris Narvaez Del Pilar

Dissertations and Theses (Open Access)

The mesenchyme comprises of heterogeneous cell populations that support neighboring structures and are integral to intercellular signaling. Despite such importance, mesenchymal cells are poorly defined morphologically and molecularly. Their signaling regulation is not well understood, lagging their counterparts in the epithelial, endothelial, and immune lineages. Leveraging single-cell RNA-seq, three-dimensional imaging, and lineage tracing, first, we delineated different lung mesenchymal cell types and classified them into three-proximal-distal axes in the neonatal and adult murine lung. Each axis is associated to the structure they support – the endothelium, epithelium and interstitium. We also identified two subpopulations of neonatal lung myofibroblasts – ductal …

Impact Of Intratumor Heterogeneity And The Tumor Microenvironment In Shaping Tumor Evolution And Response To Therapy, Akash Mitra

Dissertations and Theses (Open Access)

Intratumor heterogeneity (ITH) is a crucial challenge in cancer treatment. The genotypic and phenotypic heterogeneity underlying diverse cancer types leads to subclonal variation, which may result in mixed or failed response to therapy. The heterogeneity at the tumor level, along with the tumor microenvironment (TME), often shapes tumor evolution and ultimately clinical outcome. Given that modern treatment paradigms increasingly expose patients with metastatic disease to multiple treatment modalities through the course of their disease, there exists a need to characterize robust and predictive biomarkers of response to therapy. In order to accurately characterize tumor evolution, we need to account for …

Biases And Blind-Spots In Genome-Wide Crispr-Cas9 Knockout Screens, Merve Dede

Dissertations and Theses (Open Access)

Adaptation of the bacterial CRISPR-Cas9 system to mammalian cells revolutionized the field of functional genomics, enabling genome-scale genetic perturbations to study essential genes, whose loss of function results in a severe fitness defect. There are two types of essential genes in a cell. Core essential genes are absolutely required for growth and proliferation in every cell type. On the other hand, context-dependent essential genes become essential in an environmental or genetic context. The concept of context-dependent gene essentiality is particularly important in cancer, since killing cancer cells selectively without harming surrounding healthy tissue remains a major challenge. The toxicity of …

Discovery Of Novel Ubiquitin- And Methylation-Dependent Interactions Using Protein Domain Microarrays, Jianji Chen

Dissertations and Theses (Open Access)

Post-translational modifications (PTMs) drive signal transduction by interacting with "reader" proteins. Protein domain microarray is a high throughput platform to identify novel readers for PTMs. In this dissertation, I applied two protein domain microarrays identifying novel readers for histone H2Aub1 and H2Bub1, and H3TM K4me3. Ubiquitinations of histone H2A at K119 (H2Aub1) and histone H2B at K120 (H2Bub1) function in distinct transcription regulation and DNA damage repair pathways, likely mediated by specific "reader" proteins. There are only two H2Aub1-specific readers identified and no known H2Bub1-specific readers. Using a ubiquitin-binding domain microarray, I discovered the phospholipase A2-activating protein (PLAA) PFU domain …

Assessing Genetic Counselors' Clinical Approach And Practices Regarding Pathogenic/Likely Pathogenic Variant Downgrades, Grant Bonesteele

Dissertations and Theses (Open Access)

Although rare, variant downgrades from a pathogenic/likely pathogenic (P/LP) variant to a variant of uncertain significance can have a significant impact on patients and their families in the clinical cancer setting. However, there is a lack of literature about how to approach these potentially challenging cases as a genetic counselor. Therefore, we aimed to characterize genetic counselors’ experiences, approach, and practices to variant downgrade cases using an online survey. The survey asked participants how they would approach variant downgrade scenarios involving the CDH1 or ATM genes with variable family histories. Genetic counselors appear to be united in whether they would …

Genetic Pathway Analysis Of Abnormal Facial Development In Nonsyndromic Cleft Lip And Palate, Lorena Maili

Dissertations and Theses (Open Access)

Nonsyndromic cleft lip with or without cleft palate (NSCLP) is the most common craniofacial birth defect resulting from incomplete fusion of the facial prominences during development, which leaves a gap in the lip, primary palate and/or the secondary palate. NSCLP affects 135,000 NSCLP newborns worldwide each year based on a birth prevalence of 1 per 700 live births. While surgical treatments have dramatically improved, many long-term health issues persist, imposing significant medical, psychosocial and economic burdens. Familial aggregation and segregation analyses suggest genetic contributions underlie NSCLP, but despite decades of study, only a small portion of the NSCLP genetic liability …

Computational Approaches To Delineate Transcriptional And Functional Heterogeneity In Pancreatic Cancer, Sanjana Srinivasan

Dissertations and Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is an incurable disease characterized by poor survival, dense desmoplastic stroma and activating mutations in KRAS (>90%). These tumors are highly complex ecosystems composed of molecularly distinct sub-populations that exhibit a spectrum of genetic features and associated phenotypes. Despite recent advances in the transcriptomic characterization of PDAC into at least two tumor subtypes, this alone has been insufficient to define more specific patterns of oncogenic dependency. To fully leverage advancements in next generation sequencing and functional genomics, we have sought to establish computational methodologies to aid in refined target discovery, and to develop a novel …

Evaluating Insurance Approval Rates Of Exome Sequencing And Its Effect On Minority Patients' Access To Genetic Care, Katlyn Frane

Dissertations and Theses (Open Access)

Exome sequencing (ES) is often a standard step in the genetic testing process for patients with rare or complex disease. Despite clinical implementation of ES, insurance companies (payers) continue to deny this test. We investigated if the payer barrier is influenced by payer type, and if other demographic or clinical information correlated to ES approval and obtainment. To do this, a retrospective chart and clinical database review was completed on patients seen at a tertiary care center and community-based clinic. Patient demographics, clinical indications, and testing recommendations and outcomes were used to assess ES approval and obtainment. We found that …

Functions Of Dcp2 And Ski7 In Mrna Degradation, Minseon Kim, Ambro Van Hoof

Dissertations and Theses (Open Access)

Posttranscriptional gene regulation is essential to maintain gene expression fidelity. This is partially achieved by mRNA decay. When no longer required, mRNA is degraded by two alternative pathways. The decapping enzyme Dcp2 removes the 5` <sup>m7</sup>G cap of mRNAs, allowing Xrn1 to degrade the mRNA from the 5` end. Alternatively, mRNA is degraded from the 3` end by the RNA exosome.

While decapping by Dcp2 is a critical step in mRNA decay, its physiological function has been unclear. Null mutations of Saccharomyces cerevisiae DCP2 have been reported to be lethal in some studies but slow-growing in others. In this …

Investigating Barriers Experienced By Underrepresented Minorities In Becoming A Competitive Genetic Counseling Applicant, Katie Huang

Dissertations and Theses (Open Access)

Representation for both racial/ethnic and gender identity minorities in genetic counseling (GC) remains the lowest among similar healthcare professions. Barriers that underrepresented minority (URM) individuals face in becoming a competitive GC applicant have not yet been described. Academic capital (AC) is a theoretical framework describing the social processes necessary for individuals to navigate and succeed in higher education. This study aimed to characterize barriers experienced by applicants who self-identify as underrepresented and to explore how AC could identify areas for intervention. Prospective GC applicants for the 2021/2022 cycles were recruited to complete an anonymous online survey in Qualtrics through a …

Rare Variant Association Studies In Crohn’S Disease And Colorectal Cancer: Methods And Applications, Jiun-Sheng Chen

Dissertations and Theses (Open Access)

Genetic factors account for a substantial portion of Crohn’s disease and colorectal cancer (CRC) risk. Patients with Crohn’s disease, a condition that causes chronic inflammation of the gastrointestinal tract, are at increased risk of colorectal cancer morbidity and mortality. Genome-wide association studies using single marker approaches have identified loci responsible for these diseases, but disease susceptibility from rare variants is incompletely understood. This dissertation includes three chapters, two association studies for Crohn’s disease and CRC, and a statistical method to improve the power of statistical tests.

For Crohn’s disease, we performed targeted sequencing of 101 genes in 205 children with …

Spectrum And Incidence Of Primary And Therapy-Related Hematologic Malignancies In Individuals With Brca1 And Brca2 Pathogenic Variants, Rosemary Rogers, Rosemary Rogers

Dissertations and Theses (Open Access)

Therapy-related myeloid neoplasms (t-MN) are rare and deadly hematologic malignancies that develop following exposure to cytotoxic therapies such as radiation, chemotherapy, and poly (adenosine diphosphate-ribose)-ADP polymerase (PARP) inhibitors. Preliminary evidence suggests that germline BRCA1 and BRCA2 pathogenic and likely pathogenic (P/LP) variants may increase susceptibility to t-MNs due to the genes’ established role in DNA damage response. There is also evidence that individuals with BRCA1/2 P/LP variants may be more susceptible to developing primary hematologic malignancies. We reviewed medical records of 706 individuals with BRCA1/2 P/LP variants to assess hematologic malignancy diagnoses and t-MN development. Our study population was 5.1% …

Mixture Model Approaches To Integrative Analysis Of Multi-Omics Data And Spatially Correlated Genomic Data, Ziqiao Wang

Dissertations and Theses (Open Access)

Integrative genomic data analysis is a powerful tool to study the complex biological processes behind a disease. Statistical methods can model the interrelationships of the involved gene activities through jointly analyzing multiple types of genomic data from different platforms (vertical integration), or improve the power of a study through aggregating the same type of genomic data across studies (horizontal integration). In this dissertation, we propose statistical methods and strategies for integrative multi-omics data in association analysis of disease phenotypes, with an emphasis on cancer applications.

We develop a new strategy based on horizontal integration by leveraging publicly available datasets into …

Genetic And Clinical Determinants Of Racial/Ethnic Differences In Multiple Myeloma Susceptibility And Outcomes Focusing On Hispanics, Alem Belachew

Dissertations and Theses (Open Access)

Multiple Myeloma (MM) constitutes 10% of diagnosed hematologic malignancies in the US, with over 12,000 deaths recorded each year. Race/ethnicity is a well-known MM risk factor, where individuals of African descent have over 2- to 3-fold increased risk of incidence compared to those of European descent. Additionally, Hispanics are diagnosed approximately three years younger than white American counterparts, for unknown reasons. Differences in clinical phenotype are also present for MM patients by ancestry, including varying rates of common initiation mutations such as IgH translocations and TP53 mutation between patients of European and African descent. Studies have begun to interrogate the …

A Context-Forward In Vivo Functional Genomics Platform For Target Discovery And Establishing Vulnerability Context In Pancreatic Cancer, Johnathon Rose, Johnathon Lynn Rose

Dissertations and Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with a very poor patient prognosis (5-year survival of ≤ 7%). While transcriptional profiling has aided in the classification of this disease into at least two broader subtypes, this alone has so far been insufficient to inform on more nuanced patterns of oncogenic dependency. We hypothesized that a more comprehensive and granular characterization of PDAC disease diversity is required to establish relevant context for targeted therapy. To this end, we sought to establish an integrated platform to: i) more comprehensively characterize differential oncogenic signaling across our tumor models, and ii) establish …

P53 Drives A Transcriptional Program That Elicits A Non-Cell-Autonomous Response And Alters Cell State In Vivo, Sydney Moyer

Dissertations and Theses (Open Access)

Cell stress and DNA damage activate the tumor suppressor p53, triggering transcriptional activation of a myriad of target genes. The molecular, morphological, and physiological consequences of this activation remain poorly understood in vivo. We activated a p53 transcriptional program in mice by deletion of Mdm2, a gene which encodes the major p53 inhibitor. By overlaying tissue-specific RNA-sequencing data from pancreas, small intestine, ovary, kidney, and heart with existing p53 ChIP-sequencing, we identified a large repertoire of tissue-specific p53 genes and a common p53 transcriptional signature of seven genes which included Mdm2 but not p21. Global p53 activation …

The Genome-Wide Roles Of The Lung Lineage Transcription Factor Nkx2-1 In The Regulation Of Opposing Cell Fates In Vivo, Danielle Renae Little

Dissertations and Theses (Open Access)

Lineage transcription factors mark, promote, and maintain multiple distinct cell types originating from a common progenitor. Despite their essential role, how such factors function and bind genome wide to orchestrate the epigenetic changes necessary to form and maintain these identities in vivo is unclear. One lineage transcription factor NK Homeobox 2-1 (NKX2-1) is expressed throughout the lung epithelium during development and was thought to be lost in the extraordinarily thin cell type required for gas exchange– the alveolar type 1 (AT1) cell. Complementing precise genetic knockouts with cell type-specific ChIP-seq, ATAC-seq, and scRNA-seq, our study shows that AT1 and AT2 …

Decoding The Evolutionary Response To Prostate Cancer Therapy Using Plasma Genome Sequencing, Naveen Ramesh

Dissertations and Theses (Open Access)

Investigating genome evolution in response to therapy is difficult in human tissue samples due to the difficulty in accessing metastatic tumor sites and logistical challenges of collecting longitudinal samples. To overcome these issues, we developed an unbiased whole-genome plasma DNA sequencing approach called PEGASUS that concurrently measures genomic copy number and exome mutations from archival cryostored plasma samples. This approach was applied to study longitudinal blood plasma samples from prostate cancer patients. A molecular characterization of archival plasma DNA from 233 patients and genomic profiling of 101 patients identified clinical correlations of aneuploid plasma DNA profiles with poor survival, increased …

Investigation Of Proliferation Suppressors In Genetic Fitness Screens, Walter Frank Lenoir Iv

Dissertations and Theses (Open Access)

Innovation of CRISPR gene-editing technology has provided scientists genome manipulation tools that allowed rapid advancement of scientific capabilities and thus improved our ability to systematically study mammalian genetic functional profiles. Genome-wide CRISPR knockout screens conducted in collections of human cell lines can knock out genes at multiple loci, and have provided new insights into functional roles for independent genes. This method has launched massive efforts in looking across genetic backgrounds for context specific genetic vulnerabilities within cancer. Much of the research effort thus far has been spent on optimizing phenotype distinctions between essential, genes required for cell fitness, and non-essential, …

Longitudinal Clonal Lineage Dynamics And Functional Characterization Of Pancreatic Cancer Chemo-Resistance And Metastasization, Chieh-Yuan Li

Dissertations and Theses (Open Access)

In recent years, technological advancements, such as next-generation sequencing and single-cell interrogation techniques, have enriched our understanding in tumor heterogeneity. By dissecting tumors and characterizing clonal lineages, we are better understanding the intricacies of tumor evolution. Tumors are represented by the presence of and dynamic interactions amongst clonal lineages. Each lineage and each cell contributes to tumor dynamics through intrinsic and extrinsic mechanisms, and the variable responses of clones to perturbations in the environment, especially therapeutics, underlie disease progression and relapse. Thus, there exists a pressing need to understand the molecular mechanisms that determine the functional heterogeneity of tumor sub-clones …

Identification Of Trim24 Domain Essentiality In Primary Trim24coe Carcinosarcoma Cell Lines, Cem Dede

Dissertations and Theses (Open Access)

Regulation of transcriptional control is a critical feature for organismal development and survival. Because of its effects on chromatin-controlled expression, disruptions of this delicately tuned mechanism are an important factor in development of tumorigenesis. Therefore, there is a growing interest in targeting these control mechanisms for their potential therapeutic values.

Our lab previously discovered the epigenetic regulator function of Tripartite motif protein 24 (TRIM24) through its H3K4me0 and H3K23ac dual histone signature reader function, its negative regulatory effect on the p53 tumor suppressor, in addition to its shown oncogenic driving capacity on immortalized mammary epithelial cells when overexpressed. Although TRIM24 …

Artificial Intron Technology To Generate Conditional Knock-Out Mice, Amber N. Thomas-Gordon

Dissertations and Theses (Open Access)

Genetic engineering has been re-shaped by the invention of new tools in modern biotechnology in a way that offers precision and efficiency in modifying the genome at a single nucleotide level and/or allowing precise control of gene expression. Such gene manipulation brings about significant findings and revelations in comprehending more about embryonic development, cellular and physiological functions, and disease pathology. Current methods used to produce conditional knockouts have limitations on conditional allele placement and modification varies among genes in different organisms. Thus, a system for generating conditional alleles with fidelity remains a challenge. My goal was to examine an approach …

Statistical Methods For Resolving Intratumor Heterogeneity With Single-Cell Dna Sequencing, Alexander Davis

Dissertations and Theses (Open Access)

Tumor cells have heterogeneous genotypes, which drives progression and treatment resistance. Such genetic intratumor heterogeneity plays a role in the process of clonal evolution that underlies tumor progression and treatment resistance. Single-cell DNA sequencing is a promising experimental method for studying intratumor heterogeneity, but brings unique statistical challenges in interpreting the resulting data. Researchers lack methods to determine whether sufficiently many cells have been sampled from a tumor. In addition, there are no proven computational methods for determining the ploidy of a cell, a necessary step in the determination of copy number. In this work, software for calculating probabilities from …

Multiplexed Crispr Libraries For Cancer Functional Genomics, Jintan Liu

Dissertations and Theses (Open Access)

High-throughput forward genetic screenings are invaluable tools to systematically explore genetic interactions and to link gene disruption with disease contexts. The adaptation of CRISPR/Cas9 has improved the sensitivity and specificity of functional screenings. Despite this advance, there remains a long-standing need to improve functional screenings with smaller and more versatile pooled libraries. Capitalizing on the inherent multiplexing capability of a class 2 CRISPR enzyme AsCpf1, we developed a multiplexed, high throughput screening strategy that has avoided the usual trade-off between library size and library penetration, allowing library minimization without sacrificing gene targeting efficiency. We optimized the AsCpf1 protein for functional …

Factors That Impact Uptake Of Carrier Screening By Male Reproductive Partners Of Female Prenatal Patients, Wendi Betting

Dissertations and Theses (Open Access)

Carrier screening is a genomic technology that is used to identify individuals who are carriers of autosomal recessive conditions. Despite published recommendations, the majority of male partners do not complete carrier screening after their female partner is identified to be a carrier. Previous studieshave examined reasons why women elect or decline carrier screening, but there have been few published studies that examine factors that influence a male partner’s decision to elect or decline carrier screening, particularly when the female has been identified as a carrier. The aim of the study was to determine the factors that influence the uptake of …

Heterogeneous Nuclear Ribonucleoprotein K (Hnrnp K) Overexpression And Its Interaction With Runx1 Rna In Acute Myeloid Leukemia, Marisa Aitken

Dissertations and Theses (Open Access)

Acute myeloid leukemia (AML) is an often devastating hematologic malignancy with 5-year overall survival lingering near 20%. Acquiring a deeper understanding of molecular underpinnings of leukemogenesis will provide a basis for developing more effective therapeutic strategies for patients with AML.

Here, we identified overexpression of hnRNP K as a recurrent abnormality in a subset (~20%) of AML patients. High levels of this RNA-binding protein associated with inferior clinical outcomes in de novo AML. Thus, to evaluate its putative oncogenic capacity in myeloid disease, we overexpressed hnRNP K in murine hematopoietic stem and progenitor cells isolated from fetal liver cells (FLCs). …