Molecular Biology Commons^™

Riluzole As A Dual-Targeted Radiosensitizer For Osteosarcoma: Targeting Tumor Cells And Angiogenic Vasculature To Enhance Single High-Dose Radiotherapy Efficacy, Pooja P. Rao

Dissertations, Theses, and Capstone Projects

Osteosarcoma (OS), the most common primary bone malignancy of children and young adults, is intrinsically radioresistant, and outcomes for patients with unresectable or metastatic disease have not improved in over four decades. Single-dose radiation therapy (SDRT) is a potent modality against radioresistant, highly vascularized sarcomas, but its application in OS is constrained by dose-dependent normal tissue toxicity. Radiosensitizers achieving tumor control at lower doses therefore offer a direct route to widening the therapeutic window. Critically, OS radioresistance is not tumor-cell-autonomous. It emerges from two coordinated compartments: aberrant DNA repair and antioxidant capacity intrinsic to the tumor cell, and a radioprotective, …

Characterization And Advancement Of Molluscan Venom Gland Cell Model Systems, James V. Parziale

Dissertations, Theses, and Capstone Projects

Venomous mollusks, including cone snails and coleoid cephalopods, produce rich repertoires of bioactive peptides with profound effects on cellular physiology, yet there are few tractable experimental systems that exist to study their development, maintenance, and venom secretion. Although therapeutics such as the cone snail peptide Ziconotide demonstrate the biomedical potential of molluscan venoms, progress in understanding how venom glands form, function, and evolve has been hindered by the lack of reliable husbandry and the complete absence of in vitro cell models. Modern comparative genomics has revealed widespread convergent evolution across venomous lineages, but molluscan datasets remain underrepresented, limiting insights into …

4e-Bp1 Differentially Regulates Translation Of A Subset Of Human Mrnas, Mehreen Mahbub

Dissertations, Theses, and Capstone Projects

Elevated levels of eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) influence cap-independent translation by forming a complex with eukaryotic initiation factor 4E (eIF4E) (eIF4E•4E-BP1). Certain mRNAs—including those encoding hypoxia-inducible factor-1α (HIF-1α), fibroblast growth factor-9 (FGF-9), and two isoforms of tumor suppressors, p53 (p53_A, and p53_B)—contain structured 5’untranslated regions (UTRs) that enable translation either via cap-independent translation enhancer (CITE)-like or internal ribosomal entry site (IRES)-like mechanisms. However, how 4E-BP1 modulates these mechanisms remains unclear. Using fluorescence-based anisotropy assays, we showed that the eIF4E•4E-BP1 binds more tightly to the 5’ m⁷G-cap of these mRNAs than eIF4E …

Computational And Functional Characterization Of Terebrid Venom Peptides, Favour T. Achimba

Dissertations, Theses, and Capstone Projects

Venom peptides represent a natural repertoire of bioactive compounds that are potent modulators of ion channels. Teretoxins, venom peptides from terebrid snails, remain underexplored despite their structural and functional diversity. This thesis is the first to comprehensively explore the structure and function of teretoxins using a comparative computational sequence and structure model followed by experimental assays. The majority of the functional focus has been on identifying the ion channel molecular targets of uncharacterized teretoxins. Teretoxins, like other venom peptides, are hypothesized to manipulate the cellular function of a diversity of ion channels. Dysregulation of ion channels leads to several …

From Sequence To Allostery: How Amino Acid Differences Rewire Coupled Conformational Heterogeneity In The Ptp Enzyme Family, Shivani Sharma

Dissertations, Theses, and Capstone Projects

Protein Tyrosine Phosphatases (PTPs) are critical regulators of cellular signaling, and their activity is often modulated through allosteric mechanisms. Allostery is defined as a chemical or conformational change in one site of the protein due to a binding event at another site. Although several studies have investigated aspects of allostery in PTPs, the mechanistic foundations underlying allosteric regulation remain poorly understood. Despite a highly conserved catalytic domain across PTPs, regions with low or no conservation suggest potential "rewiring" of allosteric networks. This raises key questions about the universality versus individuality of allosteric mechanisms across the PTP family.

In this work, …

The Sonic Hedgehog Effector Smoothened Modulates Cholinergic Interneuron Activity, Physiology, And Striatum-Dependent Behaviors, Santiago Uribe-Cano

Dissertations, Theses, and Capstone Projects

The striatum is a central node in action selection and associative learning, integrating cortical, thalamic, and neuromodulatory input. Among its principal modulators, dopamine (DA) and acetylcholine (ACh) are known for their temporally coordinated yet mechanistically distinct influences on striatal output. However, the upstream signals that regulate their dynamic interplay, particularly within cholinergic interneurons (CINs)—the primary source of striatal ACh—remain incompletely characterized. This dissertation investigates the role of Smoothened (Smo), a G protein-coupled receptor (GPCR) effector of Sonic Hedgehog (Shh) signaling, in modulating ACh signaling dynamics in the striatum.

Building on evidence that midbrain DA neurons co-release Shh and that CINs …

Investigating The Role Of Early Growth Response 1 (Egr1) Gene In Riluzole-Induced Apoptosis In Osteosarcoma, Syeda Maryam Azeem

Dissertations, Theses, and Capstone Projects

Osteosarcoma is a rare but aggressive bone malignancy most commonly affecting adolescents and young adults (AYA). With 5-year survival rate stagnating over the last four decades despite the advancements in multi-modal therapy, drug repurposing offers a rapid path to new osteosarcoma treatments. Recent studies suggest that Riluzole, a drug approved for amyotrophic lateral sclerosis (ALS), may be repurposed for osteosarcoma treatment due to its ability to slow tumor progression and induce apoptosis. Previously, we have shown that Riluzole increases reactive oxygen species (ROS), activating c-Abl, which phosphorylates YAP in the nucleus. YAP then forms a complex with p73 to enhance …

Elucidating The Roles Of Eukaryotic Initiation Factors Involved In Dap5 Mediated Translation, Jacob Nk Quartey

Dissertations, Theses, and Capstone Projects

Translation initiation in eukaryotes is a highly regulated process essential for accurate protein synthesis. It is a dynamic process that involves a complex interplay between messenger RNAs (mRNAs), ribosomal subunits, and a host of initiation factors, ensuring precise start codon selection and the subsequent assembly of the translation machinery. This process has well been known to be mediated by the eukaryotic Initiation Factor (eIF4F), which consists of the cap binding protein eIF4E, the scaffolding protein eIF4GI, and the helicase factor eIF4A.The recognition and binding of eIF4E to the m⁷G cap structure of the mRNA is essential for the …

The Role Of Secondary And Tertiary Structure In The Cap-Independent Translation Of Fgf-9 And Hif-1-Alpha, Amanda Michelle Whittaker

Dissertations, Theses, and Capstone Projects

Under normoxic conditions, eukaryotes initiate translation of RNA through eIF4E recognition of the 5’ cap. However, under cellular stress, eukaryotic translation must be initiated through a 4E-independent, or “cap-independent” mechanism, involving eukaryotic initiation factor 4G (eIF4G) binding directly to the 5’ untranslated regions (5’ UTR) of the RNA. eIF4G binding then recruits the ribosome to the transcript. While this mechanism is useful for translation of apoptotic transcripts and transcripts involved in cell survival, cap-independent translation is also utilized by oncogenic RNA for tumorigenesis. Previous work by our lab and others has categorized this recruitment and initiation mechanism as either internal-ribosome-entry-site …

Voltage Set Points For Sodium Channel Inactivation: Intrinsic And Modulatory Mechanisms, Akshay Sharma

Dissertations, Theses, and Capstone Projects

During an action potential, voltage-gated sodium channels (VGSC) control sodium ion flow into the cytoplasm of cells by using membrane voltage to alter channel conformation. These membrane proteins exhibit three main functional conformations: closed, open, and fast-inactivated, with transitions between these states dependent on membrane voltage and kinetics. The channels open within 1 millisecond and swiftly transition from open to fast-inactivated within 1-2 milliseconds following membrane depolarization. Subsequent membrane repolarization resets the channels to the closed state. Notably, even at mildly depolarized potentials that preclude channel opening, VGSCs can undergo transitions between the closed and inactivated states, known as closed-state …

Machine-Learning Qsar-Based Novel Drug Identification To Inhibit Retinoblastoma Extracellular Vesicle Release And Metastatic Signaling, Kunhui Huang

Dissertations, Theses, and Capstone Projects

Extracellular vesicles (EVs) are lipid-enclosed particles that are generated by most types of cells and have been identified as an important mechanism for cell communication aside from cell direct contact. EVs contain a variety of functional macromolecules including proteins, lipids, RNA, which can be transferred from the host cells to target cells at a distance. The molecular pathways of EV biogenesis have been studied intensely in recent decades and the process involves several key genes and proteins. Cancer cell released EVs target distant tissues and upregulate signals that are attractive to cancer cell homing, playing a role in tumor progression …

Multi-Target Ligand-Guided Selection (Ligs) Against B-Cell Specific Antigens Expressed In A Single Lymphoma Cell Population, Nicole B. Williams

Dissertations, Theses, and Capstone Projects

Nucleic acid ligands called aptamers are single-stranded DNA or RNA molecules which fold into functional three-dimensional structures to facilitate their target binding with high affinity and specificity. The method used to generate aptamers is an in vitro process called Systematic Evolution of Ligands by Exponential enrichment (SELEX). A variant of SELEX, cell-SELEX has been used to select aptamers against cell-surface proteins in their native state. We recently introduced a novel method called Ligand-Guided Selection (LIGS) to identify aptamers against cell-surface markers. Herein, we expanded LIGS method into a multiplexing platform to partition multiple aptamers against B-cell-specific antigens, CD19 and CD20, …

Genetic Determinants Involved In Acquisition Of Iron In The Opportunistic Pathogen Mycobacterium Abscessus, Manal F. Farhat

Dissertations, Theses, and Capstone Projects

The opportunistic pathogen Mycobacterium abscessus subsp. abscessus (Mab) has become an emerging public health threat due to the increasing number of Mab-associated chronic pulmonary disease cases. Infection cure rates are only 50% due to the complex resistance of Mab to most antimicrobial drugs and chemotherapy.

Deeper knowledge of Mab biology is needed to illuminate potential candidates for development of improved therapeutics against Mab infections. The ESX-3 type VII protein secretion system of Mab plays an important role in host inflammatory and pathological responses during infection.

In this study, we demonstrate a functional link between the ESX-3 secretion …

Isolation And Characterization Of Fluorescent Proteins And Small Molecules From Marine Vertebrates, Sara Rose Krivoshik

Dissertations, Theses, and Capstone Projects

Fluorescence is a phenomenon in which a wavelength of light excites a fluorophore and then emits light at a higher, longer wavelength. This occurs throughout the biological world, in both the terrestrial and marine realms. Encompassing a diverse set of mechanisms from small molecules to large protein complexes; fluorescence has been used as a biological tool with a wide range of applications to study molecular and cellular biology for decades. This dissertation looks to identify and characterize novel fluorescent proteins and small molecules to allow for more efficient translation in developing new biotechnologies. Using a combination of RNA-Seq, Mass-Spec, protein …

Determining The Roles Of The Oligomerization And C-Terminal Domains In Mutant P53 Gain-Of-Function Activities, George K. Annor

Dissertations, Theses, and Capstone Projects

The tumor suppressor p53 (TP53) gene is often mutated in cancer, with missense mutations found in the central DNA binding domain, and less often in the oligomerization domain (OD) and C-terminal domain (CTD). The OD and CTD have been found to be critical for the tumor suppressor functionality of wild-type p53 (wtp53). Specific missense mutations in the DNA binding domain have been found to confer new gain-of-function (GOF) activities. Mutations that destabilize tetramer formation, or deletion of key lysine residues within the CTD, downregulate the ability of wtp53 to transactivate (increase the rate of transcription of) its target …

Biochemical And Biophysical Characterization Of Replicative Helicase Loading By Vibrio Cholerae Dcia, Crystal Structure Of A Monoclonal Antibody Bound To A C-Terminal Fragment Of Ebna-1 From Epstein Barr Virus, Nicholas Gao

Dissertations, Theses, and Capstone Projects

DNA replication initiation is mediated by the binding of an initiator protein to genomic origins of replication to begin the process of loading replicative helicases onto the genome. The loading of the helicase requires the action of an accessory protein, named a “loader”. Studies on well-characterized loaders have outlined how the bacterial DnaB replicative helicase is loaded via mechanisms of “Ring-Breaking” by E. coli DnaC (EcDnaC)/protein P from bacteriophage lambda (LP) and “Ring-Making” by B. subtilis DnaI. Mounting evidence points to a recently discovered candidate loader, named DciA, that shows a more widespread distribution throughout bacteria than DnaC and DnaI …

Generation Of Mycobacterium Smegmatis Model Systems For Testing Inhibitors Of The Mycobactin Siderophore Of Mycobacterium Tuberculosis, Gabrielle A. Germain

Dissertations, Theses, and Capstone Projects

Mycobacterium tuberculosis (Mtb) is the pathogenic bacterium causative of tuberculosis. According to the 2021 World Health Organization (WHO) Global Tuberculosis (TB) Report, there were approximately 5.8 million TB cases in 2020, and 1.3 million TB deaths among HIV negative people in that year. The rise of multi-drug resistant Mtb strains has increased the need for more potent microbials against this pathogen. Biosynthesis of iron scavenging molecules, known as siderophores (e.g., mycobactin and carboxymycobactin), has been identified as a potential drug target candidate since iron acquisition has been directly linked to the survival and virulence of Mtb. Salicyl-AMS (Sal-AMS) is …

Transcriptional Mechanisms Of Neuroprotection In Excitotoxicity Driven Neurodegeneration In C. Elegans, Zelda Z. Mendelowitz

Dissertations, Theses, and Capstone Projects

Excitotoxicity is notorious for triggering neuronal cell death in both developmental and adult-onset neurodegenerative diseases. In excitotoxicity, excessive concentrations of Glutamate in the synapse overstimulate Glutamate Receptors (GluRs) on postsynaptic neurons. While GluR mediated degenerative mechanisms remain obscure, GluR activation was surprisingly found to also have a neuroprotective effect through activation of specific transcriptional programs. To identify evolutionarily conserved transcriptional programs in neuroprotection we use a C. elegans model of excitotoxic necrosis (glt-3;nuIs5). We have identified that non-canonical activation of the transcription factor CRH-1/CREB mediates neuroprotection in our excitotoxicity model. We found the Histone Acetyl Transferase, MYS-1/KAT6, and the neuronal …

Elucidating Mechanisms Of Biofluorescence And Bioluminescence In Marine Organisms, Andrew M. Guarnaccia

Dissertations, Theses, and Capstone Projects

Biofluorescence and bioluminescence are two methods of light emission that entail separate mechanisms of action but end at the same process: a colorful display that have tremendous ecological and behavioral benefits, whether it be used to communicate with conspecifics, camouflage into a multicolored background, attract unsuspecting prey, or alert others to a predator. In biofluorescence, higher-energy, shorter wavelength light is absorbed then re-emitted as lower-energy, longer-wavelength light. Bioluminescence on the other hand entails a chemical reaction in which a small molecule is oxidized by an enzyme, creating a high-energy intermediate that sheds the excess energy in the form of visible …

Cdc6 Is Sequentially Regulated By Pp2a-Cdc55, Cdc14, And Sic1 For Origin Licensing In S. Cerevisiae, Jasmin Philip

Dissertations, Theses, and Capstone Projects

Control of DNA replication is critical for progression of the cell cycle and genomic stability. Cyclin-dependent kinases (CDKs) coordinate numerous phosphorylation events to accomplish two biological tasks for all living organisms: DNA replication and cell division. One CDK, Cyclin-Cdc28, is responsible for cell cycle progression in budding yeast. DNA replication requires a stepwise assembly of the pre-replicative complex on DNA, including Orc1-6, Cdc6, Cdt1 and Mcm2-7, during M-G1 phase. Cdc6 contains eight Cdc28 consensus sites, SP or TP motifs. Clb5-Cdc28 phosphorylates Cdc6-T7 to recruit Cks1, the Cdc28 phospho-adaptor, for subsequent multisite phosphorylation during S phase. There are two phospho-degrons at …

Scientific Development Of An Integrated Workflow For Latent Print, Questioned Document, And Dna Processing Of Paper Evidence, Ashley Morgan

Dissertations, Theses, and Capstone Projects

Touch paper evidence could be the source of probative human DNA but recovery is challenging and forensic laboratories instead prioritize processing by the Latent Print and Questioned Document disciplines. Recent advances in DNA collection methods and the increased sensitivity of STR typing kits have improved success rates for DNA testing of paper evidence; but prior to implementing DNA collection, laboratories have to decide in which order to examine paper for the different types of forensic evidence. This thesis developed and tested a multi-discipline workflow for processing paper evidence by DNA, Latent Prints and Questioned Documents experts. Preliminary sampling studies indicated …

Paddling Along The Voltage Gated Sodium Channel Galaxy With Sea Anemone Toxins: Structural Studies Of The Interaction Between The Paddle Motif From Nav1.5div And Sea Anemone Toxin, Adel K. Hussein

Dissertations, Theses, and Capstone Projects

Voltage gated sodium channels (VGSC) are membrane proteins that serve an important function in the central nervous system (CNS), peripheral nervous system (PNS), and cardiac muscles amongst others. The main function of VGSC is in the propagation of electrical signals by depolarizing excitable cells. Nine mammalian VGSC subtypes have been characterized, Na_V1.1 – Na_V1.9, that are expressed in a tissue specific manner, each with unique gating properties. Numerous diseases have been linked to defects in VGSC including epilepsy, mental retardation, long QT syndrome, and Brugada disease. Furthermore, these channels are one of the primary targets of …

Study Of The Gain-Of-Function Mutant P53 And Parp1 In Triple-Negative Breast Cancer, Devon Lundine

Dissertations, Theses, and Capstone Projects

Cancer cells often lose expression of the p53 protein or express mutant forms of p53. Some of these mutant p53 proteins, called gain-of-function mutant p53, have gained oncogenic functions. Previously, our group observed mutant p53 R273H interacts with replicating DNA and upregulates the chromatin localization of several DNA replication factors including PCNA, MCM2-7, and PARP1 (termed the mtp53-PARP-MCM axis). In this thesis, we explore the contribution of mutant p53 and PARP1 in castration-resistant prostate cancer (mutant p53 P223L and V274F) and triple-negative breast cancer (mutant p53 R273H). In the castration-resistant prostate cancer cell line DU145, we examine two mutant p53 …

Understanding The Influence Of Zinc On Grain Cadmium Accumulation And Bioaccessibility In Rice, Michael A. Tavarez

Dissertations, Theses, and Capstone Projects

The effect of cadmium and zinc on mineral concentrations in three cultivars of rice

Interactions between the essential mineral zinc (Zn) and the toxic heavy metal cadmium (Cd) play an important role in regulating transport of both minerals to rice grains. Understanding these interactions is crucial for limiting cadmium and increasing zinc transfer to the food chain. Previous studies on the matter have had conflicting results suggesting synergistic and antagonistic relationships between the minerals. The goal of this work was to identify the effect of external cadmium and zinc on the uptake and translocation of both minerals from roots to …

The Structural And Functional Role Of Photosensing In Rgs-Lov Proteins, Zaynab Jaber

Dissertations, Theses, and Capstone Projects

Light provides organisms with energy and spatiotemporal information. To survive and adapt, organisms have developed the ability to sense light to drive biochemical effects that underlie vision, entrainment of circadian rhythm, stress response, virulence, and many other important molecularly driven responses. Blue-light sensing Light-Oxygen-Voltage (LOV) domains are ubiquitous across multiple kingdoms of life and modulate various physiological events via diverse effector domains. Using a small molecule flavin chromophore, the LOV domain undergoes light-dependent structural changes leading to activation or repression of these catalytic and non-catalytic effectors. In silico analyses of high-throughput genomic sequencing data has led to the marked expansion …

The Role Of Estrogen Receptor Alpha In Regulating Messenger Rna 3’ End Processing And Controlling Gene Expression In Breast Cancer Cells, Sophia Varriano

Dissertations, Theses, and Capstone Projects

Estrogen signaling regulates various physiological processes within the female reproductive, cardiovascular, immune, and central nervous systems and is predominantly mediated by estrogen receptors (ER), ERα and ERβ. Transcriptional regulation by ERs has been widely studied, where activated ERs bind either directly to target genes through binding to estrogen response elements or indirectly through interacting with other proteins, resulting in changes in gene expression. However, the potential role of factors involved in the estrogen signaling pathway in posttranscriptional regulation has not been extensively documented. As 70-80% of breast cancers (BCs) are identified as ER(+), studying how these factors, particularly ERα, regulates …

Dual Control Of One Component Signaling: Mechanistic And Structural Insights Into El222 Active States, Uthama Phani R. Edupuganti

Dissertations, Theses, and Capstone Projects

Photoreceptors play a crucial role in signal transduction as specialized proteins which sense light as environmental stimuli and transduce the signal to control of downstream functions. Here we focus our attention on one class of these proteins, the Light-Oxygen-Voltage (LOV) domain, which is sensitive to blue light via an internally-bound flavin chromophore. Since their initial discovery in plant phototropins, many details of their photochemistry, chromophore interactions, and use with a diverse set of functional effectors have been described. However, several key details, especially a comprehensive understanding of signaling mechanism and its regulation, still remain elusive due in part to the …

Oxydifficidin-Producing Bacillus Presents Novel Antimicrobial Activity Against Neisseria Gonorrhoeae Involving The Deda Protein, Jingbo Kan

Dissertations, Theses, and Capstone Projects

Bacterial human pathogens cause severe infectious diseases which are the second most common cause of death next to cancer and cardiovascular diseases in the world, especially in developing countries. Gonorrhea particularly, is the second most common sexually transmitted infection (STI) which is caused by the microorganism Neisseria gonorrhoeae (GC). Centers for Disease Control and Prevention (CDC) estimates that more than 1.6 million new gonorrhea cases emerged in USA in 2018 (“Detailed STD Facts - Gonorrhea” n.d.). Also, the WHO (World Health Organization) shows that gonorrhea is the most antibiotic resistant STI (“PAHO/WHO | Gonorrhea” n.d.), highlighting the shortage of efficient …

Direct Recruitment Of Eif4gi And/Dap5 To The 5' Utr Of A Subset Of Human Mrna Drives Their Cap-Independent Translation, Solomon A. Haizel

Dissertations, Theses, and Capstone Projects

During unfavorable cellular conditions (e.g., tumor hypoxia, viral infection, nutrient deprivation, etc.), the canonical, cap-dependent translation initiation pathway in human cells is suppressed by sequestration of the cap-binding protein, eukaryotic initiation factor(eIF) 4E, by 4E-binding proteins. Circumvention of cap-dependent translation shutdown has been linked to tumor development and cancer progression. The stress-induced repression of cap-dependent translation has also been correlated with increased eIF4GI and its homolog, Death Associated Protein 5 (DAP5) expression levels, suggesting these factors have a role in cap-independent translation. Despite several evidence pointing towards a link upregulation of eIF4GI and /DAP5 levels during stress conditions, and the …

Using The Marcus Inverted Region And Artificial Cofactors To Create A Charge Separated State In De Novo Designed Proteins, Eskil Me Andersen

Dissertations, Theses, and Capstone Projects

To create an efficient de novo photosynthetic protein it is important to create long lived charge separated states. Achieving stable charge separation leads to an increase in the efficiency of the photosynthetic reaction which in turn leads to higher yields of end products, such as biofuels, electrical charge, or synthetic chemicals. In an attempt to create charge separated states in de novo proteins we hypothesized that we could engineer the free energy gaps in the proteins from excited primary donor (PD) to acceptor (A), and A back to ground state PD such that the forward electron transfer (ET) would be …