Molecular Biology Commons^™

The Role Of The Cdk8 Kinase Module In Maintaining Proteostasis, Stephen Willis

Theses and Dissertations

The underlying etiology of numerous disease states results from perturbations in the maintenance of cellular proteostasis. Carcinogenesis relies on these perturbations to foster uncontrolled cell growth and eventual metastases, while neurodegenerative diseases are a consequence of such perturbations. Control of these processes occurs at numerous molecular levels, commonly starting with transcription. A key transcriptional complex that is involved is the CDK8 Kinase Module (CKM). The CKM is conserved from yeast to man, forming a tetrameric complex consisting of MED12, MED13, CDK8, and CCNC. The CKM has not only been implicated in a variety of cancers but also in a spectrum …

Methodology To Investigate Protein-Protein Interactions Of Jun During Neuronal Differentiation Of Pc12 Cells, Heather L. Leskinen

Theses and Dissertations

In humans and other mammals, injury to the central nervous system (CNS) can cause a permanent loss of neuronal function, leading to cognitive defects, limb paralysis, and other neurological disabilities. In contrast, studies have shown that some non-mammalian vertebrates like zebrafish, have the remarkable ability to functionally regenerate axons after CNS injury by reactivating and sustaining the expression of regeneration-associated genes (RAGs). Some RAGs encode transcriptional regulators that dimerize to control downstream gene expression necessary for functional axonal recovery. Our lab has previously identified Jun as an important transcriptional regulator of regeneration after optic nerve injury in zebrafish. After axon …

Overexpression Of Ubtf Correlates With Aggressive Phenotypes Of Prostate Cancer Cells, Guillermo Andres Saldana

Theses and Dissertations

Prostate cancer (PrCa) is one of the most common malignancies in men globally and the second leading cause of cancer associated deaths in developed countries. Accumulating evidence have demonstrated involvement of various molecular and cellular factors in the development, progression and chemoresistance of PrCa and many of them were successfully established as potential molecular targets for therapy. Despite these advancements, the underlying mechanisms of PrCa occurrence is still unclear, which limits the diagnosis and therapy. Therefore, it is an urgent need to discover potential molecular targets which can be used in rational design of new strategies for the prevention and …

Evolutionary Conservation And Times Of Action Of Heterochronic Genes, Maria Ivanova

Theses and Dissertations

The heterochronic pathway of C. elegans is the most well-characterized system to date for controlling the sequence and timing of developmental events. However, we still have critical unanswered questions to address. First, little is known about the evolution of the heterochronic pathway, and of developmental timing in general. To determine if the roles of major heterochronic genes are conserved, I made mutants in orthologs of these genes in C. briggsae, using CRISPR/Cas9. My studies revealed a significant drift in the roles of some of the genes, although all of them are still involved in the developmental timing regulation, and several …

Interferon Gamma Signaling In Ovarian Cancer Cells, Bijaya Gaire

Theses and Dissertations

Interferon gamma (IFNγ) is a pleiotropic cytokine that can have, depending on the cellular and molecular context, both anti-tumor and pro-tumorigenic functions. IFNγ expression can be induced in cancer cells in response to radiation therapy or immune checkpoint blockade used in cancer treatment. We have previously shown that IFNγ induces expression of the Bcl3 proto-oncogene in ovarian cancer (OC) cells, resulting in their increased proliferation and migration, but the mechanisms are unknown. Here, I demonstrate that the IFNγ-induced Bcl3 expression is dependent on JAK1 and STAT1 signaling, and on p65 NFkB. Furthermore, my data show that the IFNγ-induced Bcl3 expression …

Protacs – A Novel And Rapidly Developing Field Of Targeted Protein Degradation, Hannah R. Gatley

Theses and Dissertations

There is a continued need for new technology and strategies for tackling cancer and other diseases, and within the current century a novel therapeutic strategy has emerged in the realm of targeted protein degradation called Proteolysis-Targeting Chimeras (PROTACs). This technology specifically targets and degrades disease-causing proteins via the ubiquitin-proteasome system, and has seen an explosion of research and intrigue in both academia and industry over the past two decades. The diversity of PROTAC classes based on the E3 ligase recruiting ligand and the target protein allows for a universal molecular structure that can be customized for a specific target and …

The Type Iv Pilus Secretin Bfpb: Structural Analysis And Binding Interactions, Janay I. Little

Theses and Dissertations

Enteropathogenic Escherichia coli (EPEC) causes severe diarrhea in young children. The type IV pilus (T4P) of EPEC, known as the bundle-forming pilus (BFP), plays an important role in EPEC pathogenesis. T4Ps are a family of surface appendages that are important for adhesion, colonization, biofilm formation, virulence, twitching motility and many other functions. One essential component of the BFP system is the secretin, BfpB. Secretins are a large family of integral outer membrane proteins found in T4Ps as well as type II and type III secretion systems, and filamentous phages. Details of the secretin structure have been limited to the overall …

Molecular Basis Of Viroid Rna-Templated Transcription, Shachinthaka D. Dissanayaka Mudiyanselage

Theses and Dissertations

Transcription is a fundamental process catalyzed by DNA-dependent RNA polymerases (DdRPs). Interestingly, some DdRPs can use both DNA and RNA as templates for transcription. This RNA-dependent RNA polymerase (RdRP) activity of DdRPs is used by RNA-based pathogens such as viroids and hepatitis delta virus for replication. In addition, RdRP activity of DdRPs widely occurs in various organisms to regulate gene transcription. Despite the importance of this intrinsic RdRP activity of DdRPs, associated factors and mechanisms are in their infancy stage. We employed potato spindle tuber viroid (PSTVd) as a model to study RNA-templated transcription. Here, we present evidence showing that …

Complex Regulatory Pathways Connect Vfm Quorum-Sensing And Cyclic-Di-Gmp Signaling To Bacterial Virulence In The Phytopathogen Dickeya Dadantii 3937, Biswarup Banerjee

Theses and Dissertations

The bacterial second messenger Bis-(3’-5’)-cyclic dimeric guanosine monophosphate (c-di-GMP) regulates multiple cellular behaviors in most bacteria. Bacterial c-di-GMP signaling involves enzymes that synthesize and degrade c-di-GMP, c-di-GMP binding effectors, and targets that are acted upon by the effectors. So far, the c-di-GMP signaling pathways have been understudied. In this work, we explore the c-di-GMP signaling network further in the phytopathogen Dickeya dadantii 3937. In Chapter 2, we identified VfmE as a c-di-GMP binding transcriptional activator that represses pectate lyase production under a high c-di-GMP condition. VfmE was found to bind c-di-GMP in vitro via the RxxxR motif, similar to PilZ …

Characterization Of The Responses To Chronic Stress In Caenorhabditis Elegans, Amy Laura Knight

Theses and Dissertations

Exposure to chronic temperature stress influences organismal phenotypes that are important for human health, agriculture, and ecology. In this thesis, the model organism Caenorhabditis elegans was used to study the effects of temperature stress on reproduction and lifespan. It was found that worms demonstrated a rapid shut down in egg-laying between 18-24 hours of exposure to 28°C. Despite this reproductive defect, the overall lifespan of worms was unaffected. At the molecular level, heat shock factor 1 (HSF-1), a regulator of the protective molecular pathway known as the heat shock response (HSR), was identified as important for progeny production during heat …

Studies On The Impact Of An Insect Growth Regulator And Host Plant On Reproductive Physiology Of Lygus Lineolaris, James Houston Chance Anderson

Theses and Dissertations

The tarnished plant bug, Lygus lineolaris, is an economically important polyphagous pest with a broad host range. With occurrence of insecticide resistance, strategies to limit its ability to reproduce, which would curb population growth, are becoming increasingly more valuable. Strategies toward this goal include the application of insect growth regulators (IGRs) and utilization of resistant cotton lines. This thesis summarizes experiments that elucidate the physiological underpinnings of the mode of action of novaluron, an IGR, and a cotton chromosome substitution (CS) line on the reproductive physiology of L. lineolaris. Investigations reported herein indicate that novaluron inhibits oviposition by …

Molecular Evolution And Biogeography Of The New World Eptesicus Bats, Xueling Yi

Theses and Dissertations

Molecular evolution refers to a broad field of studies ranging from microevolution (e.g., population genetics) to macroevolution (e.g., phylogeny), including the bridging field of phylogeography. In natural populations, molecular studies are also combined with biogeography that links biological diversity with geographic distributions to provide a comprehensive understanding of evolutionary processes. The field of molecular evolution has been largely advanced from early exploratory descriptions to statistical tests on biological hypotheses and integrative analyses using sophisticated modeling. However, studies of molecular evolution still face some unresolved questions and challenges, especially in non-model systems. For example, the application of new technology has largely …

Repurposing Metformin And Antifolates For The Treatment Of Hepatocellular Carcinoma, Sherouk Mohamed Tawfik

Theses and Dissertations

Hepatocellular carcinoma (HCC), one of the most prevalent types of cancers worldwide, continues to maintain high levels of resistance to standard therapy. As clinical data revealed poor response rates, the need for developing new methods has increased to improve the overall wellbeing of patients with HCC. Due to its safety, wide availability and previously reported anti-cancer effects, metformin (MET) serves to be a possible therapeutic agent when combined with other well-known anti-cancer agents. The aim of this study was to investigate the potential anti-cancer effects of MET, an anti-diabetic agent, when combined with two antifolate drugs: trimethoprim (TMP) or methotrexate …

The Role Of Irf-1 In Spontaneous Mouse Glioma, Aakash B. Vaidya

Theses and Dissertations

Glioblastoma Multiforme has been shown to be one of the deadliest primary brain cancers. One of the reasons why GBM is so deadly, is a unique immunosuppressive tumor microenvironment that promotes GBM growth and progression. Both astrocyte and microglia have been implicated in immunosuppression. In this study, we explored the role of Interferon Regulatory Factor 1 (IRF-1) in astrocytes and glioma cells on the growth of spontaneous glioma tumors. IRF-1 is regulated by the JAK/STAT pathway and induces expression of Programmed death ligand 1 (PD-L1). PD-L1 downregulates immune responses to glioma. We found that IRF-1 had no effect on spontaneous …

Targeting Bcl-2 Family Proteins In Therapy Induced Senescent Cancer Cell Models, Wade Cook

Theses and Dissertations

Non-small Cell Lung Cancer (NSCLC) originates from numerous different cell types in the lungs and is among the deadliest of cancers. Head and Neck Squamous Cell Carcinomas (HNSCC) are derived from the mucosal membranes of the oral cavity, pharynx, and larynx. Both NSCLC and HNSCC are predominately caused by tobacco smoke inhalation and as such mutations in the tumor suppressor gene TP53 are common. Since similarities exist in the root cause of NSCLC and HNSCC, they may also share similarities in treatment methods. Cisplatin is a platinum-based DNA damaging agent that has been used as a cancer chemotherapy for decades. …

A Review Of Calcineurin Biophysics With Implications For Cardiac Physiology, Ryan B. Williams

Theses and Dissertations

Calmodulin is a prevalent calcium sensing protein found in all cells. Three genes exist for calmodulin and all three of these genes encode for the exact same protein sequence. Recently mutations in the amino acid sequence of calmodulin have been identified in living human patients. Thus far, patients harboring these mutations in the calmodulin sequence have only displayed an altered cardiac related phenotype. Calcineurin is involved in many key physiological processes and its activity is regulated by calcium and calmodulin. In order to assess whether or not calcineurin contributes to calmodulinopathy (a pathological state arising from dysfunctional calmodulin), a comprehensive …

Dissection Of The Genetic Architecture Of Grain Quality In Rice, Shuai Liu

Theses and Dissertations

Rice is an important human staple food for over half of the world’s population. Amylose content (AC), gelatinization temperature (GT), grain protein content (GPC), percentage grain chalkiness (PGC), and mineral content are important parameters for evaluating rice quality, which attracts customers and breeders. Only limited genes or QTLs (OsAAP6, OsGluA2, OsASN1, Chalk5, OsHMA3, etc.) are reported regulating rice GPC, PGC, and mineral content due to the lack of genetic knowledge and molecular markers. To dissect the genetic architecture of rice grain quality regulation, genome wide association studies (GWAS) were performed using two populations …

Insights Into Halophilic Microbial Adaptation: Analysis Of Integrons And Associated Genomic Structures And Characterization Of A Nitrilase In Hypersaline Environments, Sarah Sonbol

Theses and Dissertations

Hypersaline environments are extreme habitats that can be exploited as biotechnological resources. Here, we characterized a nitrilase (NitraS-ATII) isolated from Atlantis II Deep brine pool. It showed higher thermal stability and heavy metal tolerance compared to a closely related nitrilase.

We also studied integrons in halophiles and hypersaline environments. Integrons are genetic platforms in which an integron integrase (IntI) mediates the excision and integration of gene cassettes at specific recombination sites. In order to search for integrons in halophiles and hypersaline metagenomes, we used a PCR-based approach, in addition to different bioinformatics tools, mainly IntegronFinder.

We found that integrons and …

Roles Of Secreted Proteins And Iron Utilization Proteins In Virulence Of The Fish Pathogen Flavobacterium Columnare, Rachel Conrad

Theses and Dissertations

The Gram-negative bacterium Flavobacterium columnare is the causative agent of columnaris disease and is responsible for significant economic losses in aquaculture. Little is known regarding the virulence factors produced by F. columnare, and control measures are limited. Like many members of the phylum Bacteroidetes, F. columnare uses the type IX secretion system (T9SS) to secrete enzymes, adhesins, and proteins involved in gliding motility. When a core component of this system was deleted in the wild type strain, the resulting mutant was avirulent in zebrafish, rainbow trout, and channel catfish infection studies. This suggests that the individual secreted proteins may function …

Negative Regulation Of The Kinase Lin-45 By The E3/E4 Ubiquitin Ligase Ufd-2, Augustin Deniaud

Theses and Dissertations

The serine/threonine kinase BRAF is a key part of the Ras-Raf-MEK-ERK pathway, an inducer of cell growth, differentiation, and survival. In humans, activating mutations, most commonly BRAF(V600E), have been detected in several cancers, including melanoma and thyroid cancer. In the Caenorhabditis elegans ortholog LIN-45, the equivalent mutation LIN-45(V627E) results in elevated Raf-MEK-ERK signaling. We performed an unbiased genetic screen to identify negative regulators of LIN-45(V627E). Here, we report the identification of the E3/E4 ubiquitin ligase UFD-2, and show it is a negative regulator of LIN-45 protein activity and levels. Loss of UFD-2 leads to accumulation of wild-type LIN-45 protein as …

Selection And Demography Drive Range-Wide Patterns Of Mhc Variation In Mule Deer (Odocoileus Hemionus), Rachel M. Cook

Theses and Dissertations

Variation at functional genes involved in immune response is of increasing concern as wildlife diseases continue to emerge and threaten populations. The amount of standing genetic variation in a population is directly associated with its potential for rapid adaptation to novel environments. For genes in the major histocompatibility complex (MHC), which are crucial in activating the immune response and which have extremely high levels of polymorphism, the genetic variation has been shown to be influenced by both parasite-mediated selection and historical population demography. To better understand the relative roles of parasite-mediated selection and demography on MHC evolution in large populations, …

Divergent Regulatory Roles Of Nurd Chromatin Remodeling Complex Subunits Gatad2 And Chd4 In Caenorhabditis Elegans, Nicole Lynn Golden

Theses and Dissertations

During stress, a protective cellular network known as the heat shock response (HSR) is induced to maintain protein-folding homeostasis, or proteostasis. While the HSR is essential for stress resistance, its misregulation is associated with neurodegenerative disease and cancer. Using the nematode model organism Caenorhabditis elegans, we have identified the chromatin remodeling complex NuRD (nucleosome remodeling and deacetylase) as a novel regulator of the HSR. Here, we begin with a brief introduction of the HSR and chromatin remodeling complexes in C. elegans, prior to presenting our findings in a series of two chapters. In chapter one, we outline a set of …

Distinct Spatiotemporal Regulation Of The Cytoprotective Heat Shock Response In Caenorhabditis Elegans, Rosemary Nadine Plagens

Theses and Dissertations

Every organism studied to-date utilizes the heat shock response (HSR) to maintain protein-folding homeostasis (proteostasis) during temperature or other protein-folding stress. The HSR has been well characterized using acute heat stress (HS) in single-celled models, but less is known about how distinct cell types and tissues respond to HS. Furthermore, how metazoans respond to prolonged HS at the molecular level remains relatively unexplored. The model organism C. elegans, with its genetic tractability and distinct tissues and behaviors, has been used extensively in the field to characterize the acute HSR, but with considerable variability across labs regarding HS temperature and duration. …

Structure & Function Of Enzymes In Two Uncharacterized Gene Clusters From Pseudomonas Brassicacearum & Streptomyces Griseofuscus, Lamia Tabassum Badhon

Theses and Dissertations

Pyridoxal 5’-phosphate (PLP)-dependent enzymes harness this versatile cofactor to catalyze a variety of reactions including transamination, decarboxylation, racemization and various elemination/subsitution reactions. Several years ago, a new class of PLP-dependent enzymes was discovered that uses PLP and molecular oxygen to catalyze the 4-electron oxidation of L-arginine to 4-hydroxy-2-ketoarginine. Work with the prototypical enzyme of this class, MppP from Streptomyces wadayamensis (SwMppP), showed that the dioxygen consumed during the reaction is reduced to hydrogen peroxide, and that the hydroxyl group installed in the product derives from water. Thus, SwMppP is an L-arginine oxidase, and not an oxygenase. This was surprising given …

Reducing Seed Coat Fiber Content And Pod Shatter, And Engineering Medium Chain Fatty Acids-Containing Oil, In The Oilseed Crop Pennycress ( Thlaspi Arvense L. ), Maliheh Esfahanian

Theses and Dissertations

The overall goal of this thesis was to genetically improve agronomic traits of pennycress (Thlaspi arvense L.; Field Pennycress) and demonstrate the production of value-added designer seed oils to domesticate pennycress and enable its establishment as a new winter annual oilseed/meal/cover crop to be grown in temperate regions of the world. In the U.S. Midwest, pennycress can be double cropped on existing farmland during the time between corn harvest and subsequent planting of soybeans the following spring. Pennycress has the potential to produce 2,000 lbs/acre seeds, which at 33% by weight oil content and 20% protein, would yield 85 gallons/acre …

Quantitative Pcr And Sanger Sequencing Of Mitochondrial Dna Recovered From Waterlogged Bone, Kailey Babcock

Theses and Dissertations

In forensic contexts, samples containing heavily fragmented DNA are commonly encountered. Compromised biological samples are especially prevalent in instances where human remains have been submerged in an aqueous environment for extended periods of time. Nuclear DNA is particularly vulnerable to the prolonged exposure to heat, moisture, and bacterial degradation that are prevalent in aquatic settings. Paired with the difficulty of recovering DNA from skeletal remains, which are often the only remaining component after the soft tissues have been stripped away, mitochondrial DNA (mtDNA) analysis serves as an invaluable alternative. In this multifaceted study, mtDNA analysis was performed on waterlogged bone …

Development And Evaluation Of A Combinatorial Rt-Qpcr Multiplex For Forensic Body Fluid Identification, Carolyn A. Lewis

Theses and Dissertations

Body fluid identification is essential in the forensic biology workflow that assists DNA analysts in determining where to collect DNA evidence. Current presumptive tests lack the sensitivity and specificity molecular techniques can achieve; therefore, molecular methods, such as microRNA and microbial signatures, have been extensively researched in the forensic community. Limitations of each method suggest combining molecular markers to increase discrimination efficiency of multiple body fluids from a single assay. While microbial signatures have been successful in identifying fluids with high bacterial abundances, microRNAs have shown promise in fluids with low microbial abundance. A disadvantage of RNA analysis in forensic …

A Mechanism Behind The Mechanotransduction Of Surface Characteristics In Osteoblasts, Otto J. Juhl Iv

Theses and Dissertations

Biomaterials for use in bone regeneration and healing range from metal and metal alloy implants to hydrogel-based solutions. These materials can be optimized to increase bone healing and integration by improving the mechanical and biological properties. Regardless of the material itself, the cell-substrate interaction is key to the success of the biomaterial once implanted. Substrate surface characteristics such as roughness, wettability, and particle density are well-known contributors to a substrate’s overall osteogenic potential, and therefore the substrate's overall success. Unfortunately, it is still unknown how these substrate surface characteristics are transduced into intracellular signals by cells, preventing specific tailoring of …

A Novel Review Of Heat Shock Protein 110 Kda: A Basis For Research And Continued Experimentation Through Biochemical Analysis, Crist W. Cuffee

Theses and Dissertations

Heat shock protein 110 kDa, Hsp110, is a distinct cellular protector, different in form and function from Hsp70, a close relative of Hsp110. Functioning primarily as a holdase or in tandem with other molecular chaperones, a review of current accomplishments elucidates the uniqueness of this protein and the continued mysteries that surrounds it. Found only in eukaryotes, Hsp110 has been linked to many diseases, ranging from parasitic infection to neurodegenerative disorders. While still lacking, studies of this protein have provided much in the realm of speculation on the mechanisms behind Hsp110s’ contribution to different pathologies. This review will serve as …

Dissecting Molecular Mechanism Of Heat Stress On Anther Development In Fragaria Vesca, Shikha Malik

Theses and Dissertations

Strawberry is an important fruit crop in the Rosaceae family. Originally from the temperate region, strawberry is vulnerable to heat waves, which reduce fruit yield and quality. Previous studies have shown that heat stress impairs pollen development; however, the molecular mechanisms by which heat stress affects the development of anthers, where pollen develops, are unclear. Due to the genome complexity of cultivated strawberry (Fragaria × ananassa, 2n = 8x= 56), Fragaria vesca (2n = 2x = 14) was used, which emerges as a diploid model plant for Rosaceae, to study the effects of heat stress on anther development at morphological …