Molecular Genetics Commons^™

Implications Of Type Iv Pilus Retraction For Dna Uptake By Acinetobacter Baumannii, Yafan Yu

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Horizontal gene transfer (HGT) via natural competence allows bacteria to incorporate extracellular DNA (eDNA) into their genomes, facilitating genetic diversity and adaptation. In Acinetobacter species, natural competence depends on DNA binding and uptake mediated by type IV pili (T4P). T4P are dynamic extracellular filaments composed primarily of the major pilin subunit PilA, along with a few minor subunits. T4P drive a range of cellular functions including twitching motility, biofilm formation, and DNA uptake, with some functions dependent on pilus retraction and others not. However, how Acinetobacter T4P bind DNA and how T4P/eDNA interactions impact biofilm formation remain unclear. Here, I …

Developing A Small Molecule To Inhibit Hsf1 Expression In Cancer And Evaluating Natural Genetic Variation In Small Molecule Toxicity., Michaela Kendal Foley

Theses and Dissertations

Each year cancer affects nearly 20 million people worldwide and genetic differences across populations can impact cancer onset and progression. Specifically, tumors with high levels of HSF1, the master regulator of the cytoprotective heat shock response (HSR), are correlated with poor patient outcomes in multiple cancers such as prostate, breast, and melanoma. Subsequently, the development of pharmacological inhibitors of HSF1 represents a promising strategy for anticancer therapeutics. Using a luciferase-based transcriptional reporter, two small molecule libraries were screened for inhibitors of HSF1 expression in human embryonic kidney cells, yielding ten compounds that decrease HSF1 expression. To identify if cancer lines …

African Sleeping Sickness: From Basic Biology To Future Directions, Riddhi R. Patel

All Theses

African Sleeping Sickness is a Neglected Tropical Disease (NTD) which poses a significant health risk to impoverished populations in 36 Sub-Saharan African countries. It is a devastating disease caused by the protozoan parasite Trypanosoma brucei, which is transmitted to mammals via the bite of infected tsetse flies. The disease manifests in two stages: the hemolymphatic stage and the meningoencephalitic stage. In the latter stage, it invades the Central Nervous System (CNS) and can be fatal if left untreated. It is caused by morphologically indistinguishable species of Trypanosoma brucei in both humans and animals, where in humans it is known as …

The Roles Of Rnt1 And Putative Endoribonucleases In Eukaryotic Mrna Degradation, Lee-Ann Notice-Sarpaning

Dissertations and Theses (Open Access)

Endoribonucleases initiate degradation by cleaving RNAs internally. Mutations in these enzymes have been shown to cause diseases such as cancer, developmental disorders, and neurodegenerative diseases. Yet, eukaryotic endoribonucleases have not been well studied, especially with regard to their role in nuclear mRNA degradation. Rnt1 is a Saccharomyces cerevisiae (budding yeast) nuclear endoribonuclease and homolog of human Drosha with well-characterized roles in the processing of ncRNAs. The enzyme recognizes and cleaves double-stranded RNA stems containing a terminal tetraloop with an AGNN consensus sequence. However, the scope and consequence of its function in mRNA degradation has heretofore been unclear. Previous studies have …

Elucidating The Multi-Omics Of Early-Onset Colorectal Cancer, Jumanah Alshenaifi

Dissertations and Theses (Open Access)

The incidence and mortality rates of sporadic early-onset colorectal cancer have increased in recent decades, but there is no clear etiological basis for this trend. EOCRC is commonly defined as colon and rectal cancers diagnosed before the age of 50 years. The rising incidence of EOCRC has made it the second most common cancer and the third leading cause of cancer death in this age group. The rising incidence of EOCRC is also documented internationally in more than 20 countries across different continents. Clinically, EOCRC has a distinct, more aggressive clinical profile than LOCRC. While approximately 15% of EOCRC cases …

A Stakeholder-Informed Conceptual Framework For Evaluating Genomics In Precision Oncology, Julie A. Wiedower

All Dissertations

This dissertation explores the value of genomic testing in precision oncology with an emphasis on how US payers conceptualize and prioritize elements of value. This research aims to address gaps in understanding payer perspectives and proposes a stakeholder-informed framework for evaluating genomic testing in oncology. To achieve this aim, the presented research investigates payer perspectives, value-based cancer care priorities, and the conceptual understanding of the value of a genetic diagnosis to establish a framework for value with the payer audience in mind. Chapter 1 outlines relevant background information relating to the genomic revolution and challenges in translating genomic testing technologies …

The Genomic Landscape And Prognostic Impact Of Kras, Stk11, And Smarca4 Mutations And Co-Mutations On Survival Outcomes In Non-Small Cell Lung Cancer, Peter Manolakos

All Dissertations

Non-small lung cancer (NSCLC) accounts for 85% of lung cancer cases, and Kirsten rat sarcoma viral oncogene homolog (KRAS), Serine/Threonine Kinase 11 (STK11), and SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 4 (SMARCA4) mutations and co-mutations have been increasingly recognized for their potential prognostic significance. However, clear knowledge gaps remain regarding which treatments should be selected for patients who present clinically with KRAS/STK11 or KRAS/SMARCA4 co-mutations, as outlined in Chapter 1. Despite significant clinical development advancements in immunotherapy and targeted therapy, a deeper understanding of the influence of these genomic …

Gonadal Absence Of Ceh-22: Degradation Of Ceh-22 In The Gonads Of Caenorhabditis Elegans, Andreya C. White

Undergraduate Theses

The reproductive system of hermaphrodite Caenorhabditis elegans (C. elegans) comprises two gonadal arms, each with a terminating distal tip cell (DTC), connected by a common uterus. The DTC has two functions: leader and niche. In C. elegans, ceh-22/nkx2,5 has been found to work together with Wnt signaling to determine the fates of the DTC (Lam et al., 2006). This is an indication that ceh-22 aids in the specification of DTCs. Our research aims to determine the specific function of ceh-22 in the gonad of both male and hermaphrodite C. elegans. This will be accomplished by observing …

A Natural Short Sleep Mutation Promotes Longevity Through Mitochondrial Respiration In Drosophila, Pritika Pandey

LSU Doctoral Dissertations

Aging is an irreversible process characterized by progressive physiological decline and an increased risk of metabolic disorders, cognitive impairment, cardiovascular diseases, and neurodegeneration. Disruptions to the circadian clock—whether due to genetic mutations or behavioral factors—accelerate aging and age-related pathologies, highlighting a strong link between circadian regulation and longevity. However, certain individuals harbor a dec2^P384R mutation, which enables natural short sleep without the detrimental effects of chronic sleep deprivation. This suggests that these individuals have evolved adaptations that activate pro-health pathways, allowing them to function optimally with reduced sleep. To investigate the genetic mechanisms underlying these changes, we developed a …

Robust Sex Determination In The Caenorhabditis Nigoni Germ Line, Jonathan P Harbin, Yongquan Shen, Shin-Yi Lin, Kevin Kemper, Eric S Haag, Erich M Schwarz, Ronald E Ellis

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Sexual characteristics and reproductive systems are dynamic traits in many taxa, but the developmental modifications that allow change and innovation are largely unknown. A leading model for this process is the evolution of self-fertile hermaphrodites from male/female ancestors. However, these studies require direct analysis of sex-determination in male/female species, as well as in the hermaphroditic species that are related to them. In Caenorhabditis nematodes this has only become possible recently, with the discovery of new species. Here, we use gene editing to characterize major sex-determination genes in C. nigoni, a sister to the widely studied hermaphroditic species C. briggsae. These …

Missense Mutation Of Msh6 Leucine 696 Has No Apparent Effect On The Dna Mismatch Repair Process, Razan H. Hammad, Rafia Rashid, Essence Tarrence, Christopher Bolden, Joanna E. Haye-Bertolozzi

XULAneXUS

Lynch Syndrome and Constitutional Mismatch Repair Deficiency are human diseases implicated in mutations of DNA mismatch repair (MMR) genes. This experiment tested a mutation of an MMR gene, MSH6, and evaluated how the mutation affected overall MMR effectiveness. Using the yeast Saccharomyces cerevisiae, we performed the CAN1 forward mutation assay to study msh6-L696F and its implications in the MMR process. We hypothesized that there would be a significant change in molecular function in the Msh6 protein in the presence of this mutation. Bioinformatic tools predicted that this amino acid change would have deleterious effects on MMR function. However, …

Life After Death: Investigating The Resistance And Recovery Of Fungal Communities To Foundation Tree Mortality, Jessie F. Marlenee

Biology ETDs

Tree mortality can have cascading effects on the composition and resilience of interacting fungal communities. Yet, little is known about the impact tree mortality, distinct from abiotic drivers (i.e., drought), has on these communities. This dissertation focuses on the resilience of fungal communities to experimental tree mortality in a piñon-juniper woodland. In chapter one, I found that piñon mortality reduced piñon fine root biomass and piñon mycorrhizal fungal diversity, whereas juniper mycorrhizal fungi were unaffected by juniper mortality. In chapter two, I revealed that piñon mortality altered the composition and spatial structure of mycorrhizal and saprotrophic fungi in the soil, …

Hierarchical Lineage Tracing To Unravel Mechanisms Of Cancer Treatment Resistance, Rachel Danielle Saxe

Dartmouth College Ph.D Dissertations

Cancer cells adapt to treatment, leading to the emergence of clones that are more aggressive and resistant to anti-cancer therapies. We have a limited understanding of the development of treatment resistance as we lack technologies to map the evolution of cancer under the selective pressure of treatment. To address this, we developed a hierarchical, dynamic lineage tracing method called FLARE (Following Lineage Adaptation and Resistance Evolution). We use this technique to track the progression of acute myeloid leukemia (AML) cell lines through exposure to Cytarabine (AraC), a front-line treatment in AML, in vitro and in vivo. We map distinct cellular …

Investigating Sk-3 Based Spore Killing In Neurospora Crassa Through Deletion Analysis Of Dna Intervals I383 And I394, Paulina Paulikas

Senior Theses – Biological Sciences

Neurospora fungi are found around the world. The species N. crassa is a popular model for use in genetics research. N. crassa produces sexual spores, called ascospores, during mating between strains of opposite mating types. N. crassa also produces spore sacs called asci, and each ascus typically contains eight viable ascospores. However, some Neurospora fungi carry selfish genetic elements called Spore killers, and when a strain carrying a Spore killer mates with a spore killing-susceptible strain, asci contain four black viable ascospores and four white inviable ascospores. In this project, I investigated a Spore killer called Sk-3. To act as …

Examining The Mechanism Of Spore Sacs Undergoing Sk-3-Based Spore Killing After Deletion Of Neurospora Crassa Dna Intervals I382 And I400, Makenna Klann

Senior Theses – Biological Sciences

Neurospora crassa is a well-known model organism for studying eukaryotic genetics, particularly non-Mendelian inheritance mechanisms such as meiotic drive. In N. crassa, meiotic drive can be observed in fungal spore killing, where Spore killer-3 (Sk-3) is a selfish genetic element transmitted to offspring through spore killing. Sk-3 is thought to contain two principal components: a killer (poison) gene and a resistance (antidote) gene. While the resistance gene (rsk) has been identified, the killer gene remains unknown. Building on previous research that identified a 1.3 kb DNA interval (i350) essential for Sk-3-based spore killing, I …

Determining The Effects That Deletion Of I386 And I408 Have On Sk-3-Type Spore Killing, Kole Damkoehler

Senior Theses – Biological Sciences

Neurospora crassa is a genus of fungus that exhibits a phenomenon called Sk-3 spore killing. Sk-3 spore killing occurs when an Sk-3 killer strain mates with an Sk-3 sensitive strain, and it results in the death of half of the offspring. A DNA interval called i350, located on N. crassa Chromosome III, has previously been identified as critical for spore killing. Here, to obtain a more detailed understanding of this DNA interval, the effects of the deletion of related DNA intervals i386 and i408 on spore killing has been studied. Deletion of i386 resulted in no disruption of spore …

Focal Adhesion Genes And Proteins Are Differentially Expressed Across Cell Types In Down Syndrome, Brian Yoon

Senior Theses

Down syndrome (DS), caused by an extra copy of chromosome 21, leads to widespread gene expression changes through mechanisms such as transcriptional dysregulation and altered protein interactions. These disruptions contribute to a range of clinical features, including impaired wound healing, immune dysfunction, and neurodevelopmental abnormalities. This study focused on how DS affects fibroblast morphology and motility—processes critical for tissue repair and brain development. Using quantitative immunocytochemistry and image analysis, we found that DS fibroblasts displayed a broader, less polarized shape, with increased cell perimeter and reduced aspect ratio. However, levels of key adhesion proteins like vinculin, FAK, and β-actin were …

Crispr-Induced Mutagenesis Of Arabidopsis Thaliana Gene Apetala3, Hazel Frans, Tara Phelps-Durr

SACAD: Scholarly Activities

This project aims to create CRISPR-CAS9 mutations in the APETELA3 (AP3) gene of the model plant Arabidopsis thaliana. AP3 is a class B gene critical to the petal and stamen development of Arabidopsis flowers. AP3 is defined in a MADS domain, which binds directly to DNA and may be responsible for the expression of the CaRG-box genes. AP3 works in conjunction with PISTILLATA (PI), AGAMOUS (AG), APETALA1 (AP1), and SEPALLATA (SEP) genes to specify the development in the second and third whorls of the flower. While several alleles of AP3 already exist, these alleles are strong alleles that knockout gene …

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 …

The Design, Construction, And Testing Of Mrna Vaccine Against Equine Herpes Virus, Bhawana Devkota

LSU Master's Theses

Equine Herpesvirus-1 (EHV 1) is a worldwide significant pathogen that causes respiratory illness, abortion, and neurological disorders in equine. Current vaccines, including live attenuated, inactivated, and subunit platforms, do not prevent viral latency, mucosal shedding, or cross-strain immunity, requiring alternative approaches. To address these gaps, this project explores the design, synthesis, and in vitro testing of an mRNA vaccine targeting immunogenic EHV 1 glycoprotein (gB, gC, gD, gG, and gM). Epitopes were computationally predicted using the Immune Epitope Database (IEDB), codon-optimized for Bos taurus, and cloned into pUCIDT vectors using SP6/T7 promoters. In vitro transcription (IVT) used nucleotide modifications …