Molecular Biology Commons^™

Thiol-Based Misfolding: Linking Redox Balance To Cytosolic Proteostasis, Ford Amy

Dissertations and Theses (Open Access)

The eukaryotic cytosolic proteome is vulnerable to changes in proteostatic and redox balance caused by temperature, pH, oxidants and xenobiotics. Cysteine-containing proteins are especially at risk as the thiol side chain is subject to oxidation, adduction and chelation by thiol-reactive compounds. All of these thiol-modifiers have been demonstrated to induce the heat shock response and recruit protein chaperones to sites of presumed protein aggregation in the budding yeast Saccharomyces cerevisiae. However, endogenous targets of thiol stress toxicity responsible for these outcomes are largely unknown. Furthermore, I hypothesize proteins identified as redox-active are prone to misfolding and aggregation by thiol-specific …

Hsp70-Mediated Regulation Of Hsf1 Transcriptional Activity In Saccharomyces Cerevisiae, Sara Peffer

Dissertations and Theses (Open Access)

In eukaryotic cells, protein homeostasis and cellular fitness is promoted by the transcription factor heat shock factor 1 (HSF1) during exposure to proteotoxic stress. HSF1 controls the basal and stress-induced expression of molecular chaperones and other protective targets. Dynamic regulation of HSF1 involves the major heat shock proteins Hsp70 and Hsp90. Recent advances in the understanding of this regulatory circuit in Saccharomyces cerevisiae have shown that the Hsp70 Ssa1 acts as a sensor for some proteotoxic stresses and is capable of a direct interaction with Hsf1. This work continues to explore the complex regulatory interaction between Hsf1 and Ssa1. I …

The Role Of Gene Expression Noise In Mammalian Cell Survival, Kevin Farquhar

Dissertations and Theses (Open Access)

Drug resistance and metastasis remain obstacles to effective cancer treatment. A major challenge contributing to this problem is cellular heterogeneity. Even in the same environment, cells with identical genomes can display cell-to-cell differences in gene expression, also known as gene expression noise. Gene expression noise can vary in magnitude in a population or in fluctuation time scales, which is influenced by gene regulatory networks.

Currently, it is unclear how gene expression noise from gene regulatory networks contributes to drug survival outcomes in mammalian cells. An isogenic cell line with a noise-modulating genetic system tuned to the same mean is required. …

Development Of A High-Throughput System For Screening Of Anti-Prion Molecules, Katherine Do

Dissertations and Theses (Open Access)

The misfolded prion protein causes and transmits disease in both humans and animals. As other infectious agents, prions display strain variation, which can generate different pathological outcomes in affected individuals. Unfortunately, there are no known therapies for these diseases, which at present are invariably fatal. In this work, the Protein Misfolding Cyclic Amplification technology (PMCA, an in vitro test that replicates minimum quantities of infectious prions) has been modified to screen for small molecules inhibiting prion protein misfolding in a strain-specific manner. In order to approach a high-throughput PMCA system, technical aspects in PMCA has been optimized for application of …

Preparation Of A Flavonol Specific Glucosyltransferase Found In Grapefruit And Site-Directed Mutants For Protein Crystallization, Aaron Birchfield

Electronic Theses and Dissertations

This research was designed to determine the conditions necessary to remove c-myc and 6x-His tags from a flavonol specific glucosyltransferase found in grapefruit (CP3GT) using thrombin in preparation for crystallization. X-ray crystallography of CP3GT crystals may elucidate structural features that account for flavonol specificity in some glucosyltransferase enzymes. A thrombin cleavage site was inserted into WT CP3GT and one mutant. Recombinant CP3GT was expressed in yeast and purified. Optimal conditions for thrombin digestion were explored. Digestion with 100U of thrombin for 2 hours at 4^o C was optimal for removing tags from CP3GT. Storage at 4^o C for …

An Investigation Into Clinically Relevant Determinants Of Azole Resistance In Candida Albicans, Andrew T. Nishimoto

Theses and Dissertations (ETD)

"Candida albicans is a commensal organism commonly colonizing the human gut and skin. As an opportunistic pathogen, it can cause persistent and serious infections in individuals with compromised immune systems, including the very young and elderly. Moreover, C. albicans can cause a wide spectrum of diseases ranging from superficial mucosal infections to life-threatening invasions of the organs and bloodstream. Candida species are the most common cause of invasive fungal disease, which is associated with high mortality and imposes a heavy toll on the healthcare system. Over the last 30 years, the azole antifungals have been a mainstay of antifungal therapy, …

Cellular Localization Of Rad51d Mutant Proteins And The Application Of Art To Increase Scientific Literacy In America, Claire L. Chabot

Senior Theses

Ovarian cancers are the leading cause of death from cancer of the female reproductive system. Approximately 50% of ovarian cancers have defects in the homologous recombination (HR) DNA repair pathway that is required for the repair of DNA double-stranded breaks. The status of HR genes, such as BRCA1, BRCA2, and the RAD51 family, contributes to ovarian cancer development as well as treatment decisions regarding chemotherapy, radiation, and immunotherapy. The overarching goal of this project is to identify new insights into HR that can integrate with Precision Medicine Initiatives and align with the goals of the Cancer Moonshot 2020 Program. I …

Glycine Receptor Expression Across Identified Retinal Ganglion Cell Types., Ian Scot Pyle

Electronic Theses and Dissertations

Retinal ganglion cells (RGCs) represent the culmination of all retinal signaling and their output forms the substrate for vision throughout the rest of the brain. About 40 different RGC types have been defined by differences in their visually evoked responses, morphology, and genetic makeup. These responses arise from interactions between inhibition and excitation throughout the retinal circuit (Franke et al., 2017; Masland, 2012; Sanes & Masland, 2015; Werblin, 2011). Unlike most other areas of the central nervous system (CNS), the retina utilizes both GABA and glycine inhibitory neurotransmitters to refine glutamatergic excitatory signals (Franke & Baden, 2017; Werblin, 2011; C. …

Paraoxonase 2 Is Critical For Non-Small Cell Lung Carcinoma Proliferation., Aaron Whitt

Electronic Theses and Dissertations

Non-small cell lung carcinoma (NSCLC) comprises 85% of lung cancer diagnoses and is plagued by drug resistance. Thus, elucidating the underlying mechanisms of NSCLC is paramount to expand future treatment options. Paraoxonase 2 (PON2), an intracellular enzyme with arylesterase and lactonase functions, has well-established anti-atherosclerotic activity. Recent studies show PON2 is overexpressed in a variety of tumors and confers drug resistance, although these interactions have not been thoroughly examined in NSCLC. Thus, we sought to investigate the role of PON2 in cellular proliferation using PON2-knockout mice, primary mouse cells, and NSCLC cell lines. Using these approaches, we demonstrate that PON2 …

Development Of A Lectin-Fc Fusion Protein With Antiviral And Anti-Cancer Activity., Matthew William Dent

Electronic Theses and Dissertations

This thesis describes the development of a novel lectin-Fc fusion protein and its antiviral and anti-cancer activity. The molecule, Avaren-Fc (AvFc), is a fusion of a variant of the actinomycete lectin actinohivin (Avaren) and the Fc region of human IgG1, and is selective for the terminal α1,2-mannose residues found at the ends of high-mannose-type glycans that can be found on the surface of certain heavily glycosylated viruses and cancer cells. Here, AvFc was found to be able to neutralize simian immunodeficiency virus as well as Hepatitis C virus with nanomolar IC₅₀ values. Furthermore, AvFc recognizes a number of cell …

Hormone Signaling, Gene Expression, And Mitochondrial Hormone Receptor Expression In Avian Muscle (Cells), Kentu Rushadd Lassiter

Graduate Theses and Dissertations

Mitochondria are vital to the proper growth and function of muscle cells since they’re responsible for the majority of ATP production used for cellular energy. Previous studies have investigated how differences in mitochondrial function affects feed efficiency (FE) in broilers phenotyped for High and Low FE. Low FE broilers have been shown to have increased levels of reactive oxygen species (ROS), thus contributing to higher levels of oxidative stress and damage seen in these birds. Global gene and protein expression studies conducted on breast muscle of the High FE and Low FE phenotypes have suggested that differences in mitochondrial function …

Delineation Of Events In Centripetal Migration During Drosophila Oogenesis, Travis Tait Parsons

UNLV Theses, Dissertations, Professional Papers, and Capstones

All multicellular organisms initially start out as a single cell. This cell must use the genetic information encoded in its DNA to multiply in number and build itself into a complex multicellular organism. How this process occurs is the focus of developmental biology, a field that seeks to understand how a combination of genetic information and environmental conditions shape a cell from its beginnings as a zygote all the way to maturity. A fundamental part of this process is the ability of cells to work together in order to build complex tissues and organs. Cells achieve this coordination by using …

Characterization Of Extracellular Vesicles From Human Diabetic Retinopathy Retinal Tissue In Vitro And From Urine Of Human Patients With Diabetic Retinopathy, Jason Mighty

Dissertations, Theses, and Capstone Projects

Diabetic Retinopathy (DR) is a neurovascular complication associated with diabetes mellitus that affects approximately 120 million people worldwide and its prevalence is expected to reach 190 million by 2030. DR diagnosis is accomplished with fundus ophthalmoscopy often when retinal damage and vision loss have already occurred. A group of biomarker being explored for early detection of diseases are extracellular vesicles (EVs), which are nanometer diameter lipid enclosed vesicles, released from all cell types and containing genetic cargo reflective of releasing cell state. EV biomarkers are currently being explored to help monitor disease predisposition, pathogenesis and response to treatment. While an …

The Role And Regulation Of Alternative Polyadenylation In The Dna Damage Response, Michael R. Murphy

Dissertations, Theses, and Capstone Projects

Cellular homeostasis is achieved by the dynamic flux in gene expression. Post-transcriptional regulation of coding and non-coding RNA offers a fast method of adapting to a changing cellular environment, including deadenylation, microRNA (miRNA) pathway, and alternative polyadenylation (APA). In this dissertation, I explored some of the mechanisms involved in the post-transcriptional regulation of gene expression. The main hypothesis in these studies is that a single APA event after DNA damage is governed by specific conditions and factors outside of current known regulators of APA, and that the resultant transcript has a role in the DNA damage response (DDR). My aims …

Transformation Of Model Organisms With Munc13-1 For Subcloning And Protein Harvesting, Grace Dittmar

Honors Theses

Exocytosis is the process by which cells release various molecules into the extracellular space. This mechanism is accomplished by membrane fusion, in which the membrane of the transport vesicle and that of the cell itself fuse to create one continuous membrane, allowing the release of the molecules inside the vesicle. A family of proteins, known as SNARE proteins, is responsible for facilitating membrane fusion. SNARE proteins form a complex between the vesicle membrane and the plasma membrane. For various cells, such as mast cells and neurons, exocytosis is essential to carry out their vital functions. Various accessory proteins are known …

The Dna Damage Response Gene Ddr48 Regulates Sterol Synthesis Genes To Confer Antifungal Resistance To The Pathogenic Fungus Histoplasma Capsulatum, Gabriella Reyes

Honors Theses

Histoplasma capsulatum is a dimorphic fungal pathogen that is endemic to the Ohio, Missouri, and Mississippi river valley regions. The fungus grows as a mold at environmental temperatures (25C) and transforms into a unicellular yeast upon inhalation by a mammalian host (37C). The mold to yeast shift is required for pathogenicity in host organisms, where the potentially fatal disease, histoplasmosis, can present. This study aims to characterize the DNA damage response protein DDR48 and the role that it plays in combating cellular stressors in H. capsulatum. We found that DDR48 is expressed strongly in the mold phase but expressed only …

The Role Of Parathyroid Hormone 1 Receptor (Pth1r) Signaling In Gastric Epithelial Homeostasis, Maram Maher Al-Hasan

Theses

In the stomach, the epithelial stem cells are responsible for glandular homeostasis. These stem cells continuously undergo cellular proliferation and differentiation to balance the death of senescent cells. Studies conducted on gastric cancers showed a significant increase in parathyroid hormone-like hormone (PTHLH). Moreover, both PTHLH along with parathyroid hormone (PTH) act as endogenous ligands for parathyroid hormone 1 receptor (PTH1R) which belongs to family B of G- protein-coupled receptors (GPCRs). This receptor functions by mediating many different signaling pathways and the most studied pathway is the stimulation of cyclic adenosine monophosphate (cAMP) as a second messenger.

There are very few …

Potential Interactions Between Glucocorticoid Receptors And L-Type Cav1.3 Ion Channels Expressed In Chinese Hamster Ovary (Cho) Cells, Mallory Soska

Undergraduate Distinction Papers

L-type calcium channels couple membrane depolarization to muscle contraction and aid in signal conduction between cells. Cav1.3 calcium channel isoform is expressed in neurons and endocrine cells. Nervous and endocrine tissues also express both Glucocorticoid (GR) and Mineralocorticoid receptors (MR) that are responsible for binding serum cortisol to induce immediate and long term changes within the cell. While neurons co-express both GRs and MRs, GR activation occurs in response to high concentrations of cortisol. There is a direct correlation between GR activation and the amplitude of calcium currents (Champeau, 2007). To determine potential interactions between the GR and the calcium …

Characterization Of The Perilipin 5 C-Terminus, Tim D. Clinton

Undergraduate Honors Thesis Projects

The crystallization of protein with subsequent X-Ray crystallography analysis is a powerful technique for uncovering a protein’s structure. This methodology is cutting edge and innovations are being made daily on how to best use the fundamentals of this technique for clearer characterizations. The protein Perilipin 5 could benefit from this technique as properties involving the structure of the molecule are still largely unknown. Knowing the structural aspects of perilipin 5 is important as several research efforts indicate that is a key factor in the regulation of lipolysis, or the breakdown of fats within a biological system. In the life sciences, …

Gamete Nuclear Migration In Animals And Plants, Umma Fatema, Mohammad F. Ali, Zheng Hu, Anthony J. Clark, Tomokazu Kawashima

Plant and Soil Sciences Faculty Publications

The migration of male and female gamete nuclei to each other in the fertilized egg is a prerequisite for the blending of genetic materials and the initiation of the next generation. Interestingly, many differences have been found in the mechanism of gamete nuclear movement among animals and plants. Female to male gamete nuclear movement in animals and brown algae relies on microtubules. By contrast, in flowering plants, the male gamete nucleus is carried to the female gamete nucleus by the filamentous actin cytoskeleton. As techniques have developed from light, electron, fluorescence, immunofluorescence, and confocal microscopy to live-cell time-lapse imaging using …