Digital Commons Network^™

Uvrd1 Helicase Of Mycobacterium Tuberculosis That Can Be Activated By Multiple Unique Mechanisms, Ankita Chadda

Arts & Sciences Electronic Theses and Dissertations

Abstract Mycobacterium tuberculosis (Mtb) causes tuberculosis disease in humans and is one of the leading causes of death worldwide due to infectious agents. During infection, Mtb is exposed to reactive oxygen species and reactive nitrogen intermediates from the host immune response that causes DNA damage. UvrD-like helicases are involved in DNA repair and use energy from ATP hydrolysis to translocate on single stranded DNA (ssDNA) or unwind double-stranded DNA (dsDNA) to remove the damaged DNA strand. Previous studies on UvrD-like helicases have shown that they exist in a monomer-dimer equilibrium and unwind only as dimers in the absence of accessory …

The Evolution Of Transposable Elements As Cis-Regulatory Elements In Mammals, Alan Y. Du

Arts & Sciences Electronic Theses and Dissertations

Transposable elements (TEs) are mobile genetic elements that make up a large proportion of mammalian genomes. Although TEs are highly prevalent genomic sequences, they have been understudied as they were once labeled as “junk DNA.” Despite their initial status as simple genomic parasites, recent studies have implicated TEs as cis-regulatory elements, supplying promoters, enhancers, and boundary elements. Functional testing of regulatory activity, however, remains a significant bottleneck. Nonetheless, due to their repetitive nature, TEs provide a unique model to examine the evolution of cis-regulatory elements, which has traditionally been difficult to study due to lack of homology at the sequence …

Cooperation And Conflict In The Social Amoeba Dictyostelium Discoideum And Its Paraburkholderia Endosymbionts, James Medina

Arts & Sciences Electronic Theses and Dissertations

A big question in biology is how organisms compete in an environment of competitors for scarce resources. Part of the answer lies in distinguishing friend from foe and in forging cooperative bonds in the face of cheaters. The social amoeba – bacteria system I have studied here is an excellent place to explore these tensions. The first part of my thesis research involves a review of cooperation and conflict in the social amoeba Dictyostelium discoideum and a study of the limits on obligate social cheating in this species. The second part focuses on the benefits of associating with D. discoideum …

Mechanisms For High Light Tolerance In A Fast-Growing Cyanobacterium, Patricia Walker

Arts & Sciences Electronic Theses and Dissertations

Through oxygenic photosynthesis, cyanobacteria, algae, and plants convert light into chemical energy. However, highly energetic light often damages the photosynthetic apparatus, which can lead to the decline of photosynthetic activity (photoinhibition), and prolonged photoinhibition can lead to cell death. Cyanobacteria enact various protective mechanisms to mitigate photodamage, many of which have been conserved in plants. Repair of PSII reaction centers, decreased light absorption, quenching of excess absorbed energy, and biosynthesis of antioxidants all work to mitigate damage during high light. Due to the adjustments to photosynthesis, acclimation to high light requires remodeling of cellular metabolism and physiology. Therefore, phototrophs have …

Insights Into The Non-Osmoregulatory Function Of A Pollen-Specific Mechanosensitive Ion Channel, Kari Miller

Arts & Sciences Electronic Theses and Dissertations

Pollen, the male gametophyte of flowering plants, delivers the sperm cells to the ovule to carry out sexual reproduction. During this process, the pollen grain undergoes dramatic physical changes. Survival requires careful control of cell mechanics, particularly the balance between protoplast expansion and cell wall resistance. One control mechanism is the use of a mechanosensitive (MS) ion channel, MscS-Like (MSL)8. This pollen-specific protein was previously shown to be essential for pollen survival during hydration and was proposed to function as a tension-gated osmoregulator. However, direct proof of osmoregulation during initial hydration has not yet been found. In fact, studies of …

A Structural Perspective On Neutralizing Antibodies To Flaviviruses And Coronaviruses, John Michael Errico

Arts & Sciences Electronic Theses and Dissertations

The presence of neutralizing antibodies typically correlates strongly with protection from infection, particularly for RNA viruses; elicitation of neutralizing antibody responses is thus the primary goal of most vaccines, and monoclonal antibodies (mAbs) can be leveraged as potent therapeutics. Thus, understanding the properties of individual antibodies that comprise polyclonal antibody responses and their epitopes is essential for countermeasure design. In this dissertation, I explore the epitopes and functional properties of monoclonal antibodies targeting the structural proteins of two families of RNA viruses, flaviviruses and coronaviruses.

Flaviviruses are globally distributed arthropod-borne positive-sense RNA viruses transmitted primarily by either mosquitos or ticks. …

Functional Analysis Of Recurrent Non-Coding Variants In Human Melanoma, Paula Maria Godoy

Arts & Sciences Electronic Theses and Dissertations

Worldwide incidence rates of cutaneous melanoma are increasing, and while survival rates for early stages of melanoma are high, rates drop precipitously for metastatic melanomas or those that are unable to be targeted by currently available treatments. As melanomas have a propensity to quickly metastasize, understanding the contributions of melanoma initiation remains critical for early intervention. Onset of melanoma is characterized most by mutations that stimulate mitogen-activated protein kinase (MAPK) signaling, disrupt DNA damage checkpoints, and trigger mechanisms to bypass senescence through elongation of telomeres. Additionally, in zebrafish melanoma models, the earliest cluster of melanoma-initiating cells activate expression of a …

Roles Of Behavioral Novelty And Organismal Energetics In The Evolution Of Extreme Encephalization, Erika Laurie Schumacher

Arts & Sciences Electronic Theses and Dissertations

Brains and their component brain regions vary widely in size and structure across vertebrates. However, extreme increases in total brain size relative to body size (extreme encephalization) and increases in specific major brain region sizes independent of other brain regions (mosaic brain evolution) are relatively rare. There are several hypotheses as to why, but the energetic cost of increased brain tissue and the regional interconnectedness in both brain development and function likely constrain how brains are able to change in response to selection. In this dissertation, I sought to address both how behavioral novelty relates to evolutionary changes in brain …

Bioinformatics And Cancer Genomics Approaches To Advance Precision Medicine And Elucidate Tumor Mutational Landscapes, Kelsy Cotto

Arts & Sciences Electronic Theses and Dissertations

Next-generation sequencing of DNA and RNA continues to be integrated into pre-clinical and clinical research. However, challenges still remain that impede the translation of findings into an improved understanding of human diseases or clinically actionable alterations. The projects described in this dissertation start with compiling efforts from experts who have identified druggable genes within the human genome, followed by in-depth analyses which characterize the pan-cancer landscape of splice-associated mutations and noncoding, regulatory mutations across multiple subtypes of breast cancer. In Chapters 2 and 3, substantial efforts were made to update the content and the user experience for the drug-gene interaction …

Characterizing Complex Affective Processing Across Age And In Relation To Social Anxiety Symptoms, M. Catalina Camacho

Arts & Sciences Electronic Theses and Dissertations

Humans require a shared understanding of others’ emotions for adaptive social functioning. For instance, if someone tells a joke and another person laughs, we assume the laughing person was happy because we have a shared concept for such positive interactions. Children develop and refine these concepts as they grow up, but the underlying neural processing that supports this development is unknown. Identifying the neurodevelopment underlying emotion processing could provide important insight to emotional disorders. For example, social anxiety is associated differences in the detection and interpretation of negative or neutral emotional cues, but the underlying neurodevelopment of this behavior is …

Inferring Adaptation In Social Microbes From Experimental Evolution Under Relaxed Selection, Tyler John Larsen

Arts & Sciences Electronic Theses and Dissertations

Microbes exist against a backdrop of other organisms, and the interactions between microbes have major consequences on their traits, their evolution, and their impact on the world. Microbial interactions and the adaptations that enable them are extremely diverse – they can unlock abilities beyond the reach of individual cells or lead to a population’s destruction, they can be temporary or permanent, they can be between genetically identical cells or different species entirely. The first chapter of this dissertation reviews microbial interactions and the related concept of the evolution of conflict and cooperation.To be certain a trait is an adaptation at …

Generation, Characterization, And Treatment Of Functional Zebrafish Models For Musculoskeletal Disorders, Julia Nicole Whittle

Arts & Sciences Electronic Theses and Dissertations

Musculoskeletal disorders in humans present with a broad range of phenotypes that vary in severity, onset, and genetic cause. The musculoskeletal system is comprised of complex and diverse tissues that make up the majority of total body mass. Thus, mutations in many different genes with differing structure and function can produce phenotypically similar developmental and morphological defects in the muscle and skeleton. In addition, the muscular and skeletal systems develop non-autonomously, wherein development and function of each will affect development of the other. Thus, mutations in genes responsible for development of this complex system have the potential to influence morphogenesis …

Canonical And Noncanonical Mechanisms Of Resistance To Arginine Starvation In Cancer, Leonard Christopher Rogers

Arts & Sciences Electronic Theses and Dissertations

The enzyme argininosuccinate synthetase 1 (ASS1) catalyzes the condensation of citrulline and aspartate into argininosuccinate as part of the urea cycle and citrulline-nitric oxide cycle. This reaction is essential for mammals to synthesize the amino acid arginine, which is required for all cells. Nearly all human tissues express at least some ASS1, but they import most of their arginine from the extracellular space after it is produced and released by the kidneys. Most solid tumors lack a functional level of ASS1, including over 85% of sarcomas, which are cancers of connective tissues. Published evidence suggests that this provides a proliferation …

Using Proteomics To Discover New Connections In The Arabidopsis Circadian Clock, Maria Lynn Sorkin

Arts & Sciences Electronic Theses and Dissertations

The plant circadian clock is an endogenous timekeeping mechanism that uses daylength and temperature cycles to synchronize internal physiology with the external environment. Much of our understanding of the clock in the model plant Arabidopsis thaliana comes from genetic approaches. In this thesis, I use affinity purification coupled with mass spectrometry (APMS) to identify protein-protein interactions for core clock components on a proteomic scale. I developed and optimized a protocol to perform APMS on a core set of circadian clock proteins: CIRCADIAN CLOCK ASSOCIATED 1 (CCA1), LATE ELONGATED HYPOCOTYL (LHY), PSEUDORESPONSE REGULATOR 5 (PRR5), PRR7, PRR9, TIMING OF CAB 1 …

The Role Of The Neurodevelopmental Disorder Gene Myt1l In Mammalian Brain Development, Jiayang Chen

Arts & Sciences Electronic Theses and Dissertations

Recent human genetic studies have associated mutations in a gene called Myelin Transcription Factor 1 Like (MYT1L) with neurodevelopmental disorders (NDDs). Patients with MYT1L loss of function (LoF) mutations (MYT1L Syndrome patients) demonstrate shared symptoms such as microcephaly, attention deficit and hyperactivity disorder (ADHD), and obesity. Despite prior studies showing MYT1L overexpression facilitates neuronal differentiation in vitro, its functions in vivo, especially in the mammalian brain, and how its mutation leads to human disease pathology remains poorly understood. Here, I established the first mouse model of MYT1L Syndrome mimicking a patient specific LoF mutation. I found mice with Myt1l heterozygous …

Tissue Resident Macrophages Drive Fibrosis During Pancreas Inflammatory Injury And Pancreatic Ductal Adenocarcinoma, John Baer

Arts & Sciences Electronic Theses and Dissertations

The immune system, and especially macrophages, are central in responding to infections, as well as providing a wide array of functions in other pathologies, especially in responding to inflammation. It is established that macrophages will accumulate within tissues during inflammation, many times secreting cytokines and chemokines central to the inflammatory response. This is particularly true during pancreatitis, or inflammation of the pancreas, where it has been shown that macrophages and monocytes accumulate in the pancreas to have various roles in further promoting inflammation. It is not well established, however, whether there are divergent roles for the distinct macrophage subsets that …

Connections Between Mechanosensitive Ion Channel Msl10 And Er-Plasma Membrane Contact Sites, Jennette Marie Codjoe

Arts & Sciences Electronic Theses and Dissertations

Mechanosensitive (MS) ion channels are an evolutionarily conserved way for cells to sense mechanical forces and transduce them into ionic signals. A plasma membrane-localized MS channel from Arabidopsis thaliana, MscS-Like (MSL)10, senses cell swelling and initiates a signaling cascade that triggers programmed cell death. Whereas the channel properties of MSL10 have been well studied, how MSL10 signals remains largely unknown. I worked collaboratively to show that important lesions for cell death signaling in the cytosolic N- and C-terminal domains of MSL10 interact genetically. I also helped show that ionic flux through MSL10 is dispensable for signaling, which suggested that MSL10 …

The Enemy Within: An Investigation Of The Intracellular Bacteria In Urinary Tract Infections, Jennie Elizabeth Hazen

Arts & Sciences Electronic Theses and Dissertations

Urinary tract infections (UTIs) are common diseases that are associated with significant morbidities. Multiple studies have indicated that multiple species of uropathogenesis bacteria invade and persist within bladder epithelial cells as a necessary step of uropathogenesis. Interestingly, many of these species are not canonically associated with intracellular infections. Although the first study describing bacteria within the urothelium was published two decades ago, this critical step of uropathogenesis remains relatively understudied.

I established a murine model of community-acquired A. baumannii UTI, a previously unstudied manifestation of the disease. While immunocompetent mice resolved their infections quickly, immunocompromised mice displayed high bacterial burdens …

Analyzing The Interconnectedness Of The Human Genome, Nicholas Jacobs

Arts & Sciences Electronic Theses and Dissertations

The human genome is much more interconnected than many people realize. In this thesis, I will outline two efforts to portray this idea. First, I will seek to display that cell fitness is an omniphenotype. That is to say, cell fitness can be used to determine whether an unknown factor interacts with a known factor for any phenotype. The human genome is sufficiently interconnected that if two factors interact with one another then that can be reflected by a multiplicative change in cell fitness. This change in fitness can be used to determine if a new factor of interest is …

Host Development And Microbiota Influences On Norovirus Infection, Elizabeth Alexandra Kennedy

Arts & Sciences Electronic Theses and Dissertations

The mammalian gut is a complex organ which changes over the course of development and is influenced by the presence of a dense community of gut-resident microbes. Enteric viruses infect the gastrointestinal tract in the context of the commensal microbiota and host immunity. Here, we dissect the influence of host developmental stage and the gut microbiota in norovirus infection. From this work, we determine that murine norovirus (MNoV) infection in early life is restricted by an absence of the target MNoV cell tuft cells and intact interferon (IFN) signaling. However, viral inoculum taken up by non-specific endocytosis in the neonatal …

Genetic And Transcriptomic Aspects Of Major Depressive Disorder: In Vivo Functional Assays Of Risk-Associated Variation, Candidate Disease Cell Types, And Their Pharmacologic And Sex Interactions, Bernard Mulvey

Arts & Sciences Electronic Theses and Dissertations

Major depressive disorder (MDD) is a debilitating illness that affects hundreds of millions globally, with substantial personal, medical, economic, and societal consequences. While depression occurs more commonly in females, the biology of the brain and sex underlying this skewed prevalence remains unclarified. This body of work explores two aspects of how biological sex may influence the brain at the level of gene expression: through intrinsic sex differences and through sex-mediated effects of depression risk genetics.

The monoamine hypothesis of depression suggests that modulatory neurotransmitters including serotonin and norepinephrine constitute a key axis in development of MDD. Large-scale studies of MDD …

Dysregulation Of Gene Expression In Non-Photosensitive Trichothiodystrophy, Brittany Townley

Arts & Sciences Electronic Theses and Dissertations

The pre-mRNA life cycle requires intron processing; yet, how intron processing defects influence splicing and gene expression is unclear. Here, we find TTDN1, which is frequently mutated in non-photosensitive trichothiodystrophy (NP-TTD), functionally links intron lariat processing to the spliceosome. The conserved TTDN1 C-terminal region directly binds lariat debranching enzyme DBR1, while its N-terminal intrinsically disordered region (IDR) binds the intron binding complex (IBC). The IDR forms condensates in vitro and is needed for IBC interaction. TTDN1 loss causes significant intron lariat accumulation, as well as splicing and gene expression defects, mirroring phenotypes observed in NP-TTD patient cells. Ttdn1∆/∆ mice recapitulate …

A Universal Mechanism Of G Protein Inhibition, Tyson Daniel Todd

Arts & Sciences Electronic Theses and Dissertations

G protein coupled receptors transduce a truly staggering number of diverse extracellular signals including chemical messengers, physical force, and even photons into specific cellular responses through their coupling to heterotrimeric G proteins. G proteins amplify the originating signal through their binding to downstream effectors, activating a complex network of overlapping responses that allow the cell to respond perfectly to that specific stimulus. It is critical to the cell that this process is carried out faithfully in order to respond to the myriad environmental cues and avoid injury, exhaustion, and death for the individual cell or the development of pathology if …

Understanding Gene Regulation With High-Throughput Genome-Integrated Reporter Assays, Clarice Hong

Arts & Sciences Electronic Theses and Dissertations

Proper spatiotemporal gene expression depends on specific interactions between cis-regulatory sequences (CRSs) and chromatin modifications at a genomic location. However, we do not yet understand the rules that determine how CRSs work together to influence gene expression. The goal of this thesis is to systematically assay and quantify how different genomic environments interact with CRSs to control gene expression output using a variety of genome-integrated massively parallel reporter assays (MPRAs). First, we tested the hypothesis that core promoters confer specificity by only responding to compatible enhancers and chromatin in specific genomic environments. We measured the activities of hundreds of core …

Understanding The Role Of Involucrin In Skin Inflammation, Alina Schmidt

Arts & Sciences Electronic Theses and Dissertations

Terminally differentiated keratinocytes are essential for skin barrier function and are surrounded by an involucrin (IVL)-rich cornified envelope. Increased IVL expression in the epidermis is associated with recent positive selection in European populations, yet the functional significance of this finding is unclear. An upstream enhancer of IVL, the 923 enhancer, regulates IVL expression, and the impact of IVL enhancer variants on involucrin expression in modifying the penetrance of filaggrin (FLG) loss-of-function variants associated with atopic dermatitis (AD) has not been explored. I hypothesize involucrin to modulate the environmentally sensitive Vitamin D receptor (Vdr) activity in the epidermis and involucrin enhancer …

Multi-Omics Investigation Of Tumor Heterogeneity, Oncogenic Signaling, And Treatment Response In Human Cancers, Yige Wu

Arts & Sciences Electronic Theses and Dissertations

Cancer is a highly complex disease with aberrations at the genetic, epigenetic, transcriptomic, and protein levels that drove its phenotypic diversity. Clear cell renal cell carcinoma (ccRCC) is the most common form of kidney cancer, comprising roughly 80% of cases. To define the epigenetic and transcriptomic regulation of ccRCC at the single nucleus (sn) level, we performed snRNA-seq and snATAC-seq in 34 and 28 samples respectively, including primary tumors and normal adjacent tissues, and matched them with bulk proteogenomics data. We identified tumor-specific markers and tumor subpopulations using snRNA-seq, which demonstrated diverse pathway activity within and across patients. PBRM1 and …

The Myriad Of Things: Paleoethnobotany Of The Chenopodium Album Aggregate In Northern China, Mana Hayashi Tang

Arts & Sciences Electronic Theses and Dissertations

Carbonized macrobotanical remains of the Chenopodium album aggregate (Amaranthaceae) are highly ubiquitous at archaeological sites. These chenopods are early successional plants and ruderals, which grow well in disturbed ecosystems, including those that they co-habit and co-create with humans. Often distinguished from known agricultural crops (e.g., rice, millet) as a weed, chenopods have received less attention in early food culture studies, despite their ethnohistory as a grain crop, vegetable, and famine food. Their seed remains in northern China exhibit regionally variable morphological attributes, different from those seen in chenopod cultivars of the Americas. Their morphological variability may be a result of …

Antigen Presentation In Central Nervous System Antitumor Immunity, Jay Aaron Bowman-Kirigin

Arts & Sciences Electronic Theses and Dissertations

Glioblastoma multiforme (GBM) patients face limited treatment options and poor outcomes. The median survival is less than two years, and there are no FDA approved immune therapies. Although GBM itself is an immune-suppressive, heterogeneous tumor, the lack of FDA approved immune therapies might be in part because the cancer immunity cycle is less well understood for GBM than for other tumor types. My studies focused on developing mouse models of malignant glioma that more faithfully recapitulate human GBM from an immunologic perspective, and on defining the role of the conventional dendritic cell 1 subset (cDC1) and lymphatic drainage in central …

Techniques For Spatial Analysis Of C. Elegans Anatomy And Reporter Expression, Nicolette Marie Laird

Arts & Sciences Electronic Theses and Dissertations

Quantitative analysis of microscopy images is integral to investigating biological phenomena. Despite a variety of tools to aid in analyzing C. elegans images, quantitative microscopy studies are still difficult due to the flexible and deformable nature of the nematode. These differences in posture and shape must first be corrected before analysis. Manual approaches to solve these problems are time intensive and infeasible for large datasets. Additionally, current automated tools rely on high-magnification imaging using labeled nuclei as fixed markers for comparison. Labelling can be achieved either with transgenic animals or fluorescent dyes; however, both of these can be impractical for …

Unraveling Population Heterogeneity Using Single-Cell Analysis, Wenjun Kong

Arts & Sciences Electronic Theses and Dissertations

The human body contains approximately 100 trillion cells, encompassing distinct cell types that serve diverse functions. Understanding cell population heterogeneity is vital for uncovering different biological functions and mechanisms. In addition, cells at transition during continual processes, such as development, reprogramming, and disease, are essential for painting the entire blueprint and highlighting critical stages of the progression trajectory. For instance, cell fate engineering holds much promise for generating clinically valuable cell types from mature somatic cells. Nonetheless, current reprogramming protocols are inefficient, and charting the changes in cell identity during such processes can help design strategies to mitigate the off-target …