Molecular Biology Commons^™

Rna G-Quadruplexes Function As A Tunable Switch Of Fus Phase Separation, Jenny L. Carey, Miyuki Hayashi, Emily A. Welebob, Laura R. Ganser, Huan Wang, Kerry Buckhaults, Jacquelyn A. Depierro, Zheng Shi, James Shorter, Sua Myong, Aaron R. Haeusler, Lin Guo

Department of Biochemistry and Molecular Biology Faculty Papers

Fused in sarcoma (FUS) undergoes liquid-liquid phase separation (LLPS) to support essential cellular functions, but aberrant phase transitions promote toxic aggregation in neurodegenerative disease. Short RNA oligonucleotides can reverse this behavior, yet the structural determinants that govern RNA activity remain poorly defined. Here, we identify RNA G-quadruplexes (rG4s) as tunable structural motifs that potently modulate FUS LLPS. rG4 activity depends on its concentration and is modulated by rG4 length and stability: increasing repeat number switches rG4s from inhibitor to nucleator of FUS assembly, whereas chemical modifications that stabilize rG4 enhance inhibitory function and render these activities resilient to ionic perturbation. …

Influence Of Smoking On Mlh1 Gene Polymorphism: Insights Into Colorectal Cancer Incidence, Ali Mohammed Al-Abedi, Rand Muhammed Abdul-Hussein Al-Husseini

Al-Bahir

Background: Colorectal cancer (CRC) is a leading cause of cancer-related mortality worldwide. The MutL Homolog 1 (MLH1) gene plays a critical role in DNA mismatch repair (MMR). Evidence suggests cigarette smoking increases CRC risk, potentially interacting with genetic factors.

Materials and Methods: This case-control study involved 50 Iraqi CRC patients and 50 age- and gender-matched healthy controls. The PCR-RFLP technique was employed for genotyping the -93G/A (rs1800734) polymorphism. Statistical analysis included Chi-square, Fisher's Exact Test, and logistic regression adjusted for confounders. Hardy-Weinberg Equilibrium (HWE) was assessed in controls.

Results: The frequency of the rs1800734 variant was significantly higher in CRC …

A Rho5-Cnc1-Dnm1 Signalling Module Coordinates Multi-Organelle Execution Of Regulated Cell Death In Yeast, Justin Bauer

Theses and Dissertations

Regulated cell death is a conserved process with major implications for health and disease, yet how yeast cells integrate stress signals to determine survival versus death remains unclear. This thesis investigates Cyclin C (Cnc1), a conserved Mediator kinase module component with both transcriptional and mitochondrial roles. Together with Cdk8 Cnc1 primarily represses stress response genes, while upon stress it translocates to the mitochondria to induce mitochondrial fragmentation with the dynamin-related GTPase Dnm1. Using structure-guided separation-of-function mutants, I demonstrate that Cnc1-dependent death requires its mitochondrial function rather than its transcriptional role, and that its effector Dnm1 acts as a signaling node …

Elucidating The Function Of Yedk In Response To Dna Damage, Hank Munro

University Honors Theses

Apurinic/Apyrimidinic (AP) sites are one of the most prevalent forms of DNA damage. These lesions arise spontaneously or during base excision repair of modified DNA bases and are potentially mutagenic in both mammalian and bacterial cells. 5-hydroxymethylcytosine binding, ES cell specific (HMCES), a protein found in eukaryotic cells, has been shown to form a stable DNA-protein crosslink with AP sites in single stranded DNA and to reduce the number of AP sites occurring either spontaneously or after alkylative DNA damage, resulting in increased genome stability. YedK, the Escherichia coli ortholog of HMCES exhibits some of the same biochemical properties as …

The Neuroprotective Effect Of Cdc42 Inhibition In The G93a Mutant Hsod1 Mouse Model Of Als, Andrea Koly

Undergraduate Theses, Capstones, and Recitals

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disease characterized by the selective loss of upper and lower motor neurons, leading to muscle weakness, neuromuscular junction (NMJ) degeneration, paralysis, and eventual death due to respiratory failure. Despite extensive research, effective disease-modifying therapies remain limited, underscoring the need to identify novel molecular targets involved in ALS pathogenesis. Dysregulation of Rho family GTPases has been implicated in neurodegeneration, with Rac and Rho exerting opposing effects on neuronal survival; however, the role of the closely related GTPase Cdc42 remains poorly understood in ALS. In this study, the therapeutic potential of inhibiting …

Structure-Based Discovery Of Malate Dehydrogenase Inhibitors With Efficacy Against C. Parvum Oocysts, Ankita Bharatbhai Kheni

Biochemistry and Molecular Biology

Cryptosporidium parvum, the etiological agent of Cryptosporidiosis (diarrheal illness) represents a significant global health burden, particularly affecting immunodeficient and pediatric populations. Since the parasite has a highly reduced mitochondrion and relies on glycolysis, enzymes such as C. parvum malate dehydrogenase (CpMDH), which are believed to be indispensable for parasite viability due to their pivotal roles in NAD⁺ regeneration and redox balance, remain largely unexplored as therapeutic targets. The present study employed a multifaceted experimental and computational strategy to evaluate the inhibitory activity of two lead-like and drug-like small molecules, referred to as compound 1.8 and compound 1.5, against the cofactor …

High Mobility Group Motif Proteins’ Role In Fibrosis, Inflammation, And Vascular Injury In Systemic Sclerosis, Fabian A. Mendoza, Sonsoles Piera-Velazquez, Sergio A. Jimenez

Jefferson Institute of Molecular Medicine Papers and Presentations

Systemic Sclerosis (SSc) is an idiopathic systemic autoimmune disease characterized by progressive cutaneous and systemic fibrosis, severe vasculopathy, and multiple humoral and cellular immunological alterations. The pathogenesis of SSc is highly complex and remains incompletely elucidated. The fibrotic process is a crucial component of SSc and is responsible for organ failure and high mortality. Although an increasing understanding of the fibrotic process has enabled the clinical development of antifibrotic therapeutic agents, these agents have limited clinical efficacy. Recently, the potential role of a group of transcription factors containing a High Mobility Group (HMG) motif, in the development and pathological manifestations …

Chromatin Insulators Homie And Nhomie Can Interact With Distant Copies Either Together Or Separately, With Distinct Outcomes For Enhancer-Promoter Interactions, Miki Fujioka, Wenfan Ke, Paul Schedl, James B. Jaynes

Department of Biochemistry and Molecular Biology Faculty Papers

Chromatin insulators, a.k.a. boundary elements, separate regions of the chromosome with distinct chromatin characteristics, including distinct histone modifications. This activity affects gene expression by allowing chromatin domains to be stably regulated and maintained. Insulators also block enhancer-promoter interactions and, somewhat paradoxically, facilitate other interactions, particularly when they stitch together distant regions of the chromosome by pairing with specific partners. Here we explore how long-range interactions facilitated by insulator pairing are affected by the presence of two potentially competing partners. Our results show that when two partners are present, they can reduce each other's effects on distant gene expression, suggesting that …

Targeting Inflammatory And Growth Signaling Pathways In Breast Cancer Through Diet, Microbiome, And Metabolite Interactions, Brittany Lorraine Witt

ETDs from 2020-2029

Breast cancer (BC) accounts for 1 in 3 (or 30%) of all new female cancers each year and is the most common malignant cancer in women in the United States. Since the 1990s, there has been a 44% decrease in BC, but there is still a significant gap between certain groups in terms of mortality rates. Black women have a higher mortality rate and risk for triple-negative breast cancer (TNBC). This may be due to social (inadequate access to health care facilities, insurance, or completion of therapy) and biological (genetic mutations, tumor characteristics, or comorbidity) factors between races and other …

Detection And Evaluation Of Hazardous Mercury Contamination In Various Biological Samples, Krish Italiya

Biochemistry and Molecular Biology

Mercury is a toxic environmental pollutant that threatens ecosystems and human health. This study investigates mercury contamination in Lactuca sativa (lettuce) and selected fish species, including tuna and salmon, focusing on plant responses and the limitations of X-ray fluorescence (XRF) analysis. In a controlled experiment, lettuce plants were exposed to mercury to evaluate uptake and toxicity, and XRF spectroscopy was used for quick, non-destructive elemental analysis. Results confirmed mercury accumulation in lettuce, along with visible stress symptoms such as leaf yellowing, purple pigmentation, and tissue damage. Mercury was not detected in tuna and salmon samples, likely due to concentrations below …

Elucidating The Role Of The Rnf20 Histone Modifier In Pancreatic Beta Cells, Tanya Hans Pierre

ETDs from 2020-2029

Diabetes is defined as a loss of functional beta cell mass. It is classically categorized into Type 1 Diabetes (T1D), immune-mediated beta cell destruction and Type 2 Diabetes, which is characterized by whole body insulin resistance alongside beta cell dysregulation. The incidence of diabetes worldwide has risen annually. Despite the presence of therapeutic interventions, diabetes’ heterogeneity can prompt ineffective glycemic control and the development of diabetes-associated comorbidities. For that reason, new approaches to glycemic control for individuals with diabetes are required. One approach to restore glucose homeostasis is beta cell replacement therapy, in which stem cells are programmed into beta-like …

Dock7 Is A Novel Modifier Of Duchenne Muscular Dystrophy Pathology, Katherine English

ETDs from 2020-2029

Duchenne muscular dystrophy (DMD) is a progressive, x-linked neuromuscular disorder affecting 1/5000 male births every year. DMD results from mutations in DMD, a critical structural protein within the muscle. In the absence of Dystrophin, the muscle degrades, increasing inflammation, destabilizing the cell membrane and going through constant cycles of regeneration which depletes the stem cell population. Over time, muscle tissue is replaced by fibrosis and adipose tissue, leading to loss of ambulation, respiratory and cardiac failure leading to death by early 20s. The standard of care for DMD patients is corticosteroid treatment. However, gene therapies have recently emerged which present …

Structure Of Ergosteryl-Aspartate Synthase Reveals How An Entrapped Trna Is Used Like A Prosthetic Swinging Arm In The Synthesis Of Aminoacylated Sterols, Hanako Murayama, Nathaniel Yakobov, Nassira Mahmoudi, Sasha Legrosdidier, Nicolas Fournier, Solène Zuttion, Kanata Matsumoto, Michihiro Nishimura, Jingwei Ji, Bruno Senger, Laurence Huck, Howard Gamper, Yoshiaki Kise, Ralph Kleiner, Mathieu Frechin, Ya-Ming Hou, Hubert Becker, Yuzuru Itoh, Frédéric Fischer, Osamu Nureki

Department of Biochemistry and Molecular Biology Faculty Papers

Ergosteryl-3β-O-L-aspartate synthase (ErdS) catalyzes tRNA-dependent aspartylation of ergosterol, a lipid essential for fungal cell membrane integrity. However, the functional significance of ergosteryl-aspartate and the molecular mechanisms underlying its synthesis remain unclear. Here, we show that ErdS localization is highly dynamic and that Erg-Asp is required for proper hyphal growth, sporulation, and spore germination, and likely influences stress tolerance. The cryo-electron microscopy structure of ErdS revealed an unprecedented sterol-binding pocket. In addition, the structures in complex with a non-hydrolyzable Asp-N-tRNAAsp show a tRNA-guided intramolecular aminoacyl transfer mechanism between two functional domains of the enzyme. The CCA end of tRNAAsp undergoes a …

High-Throughput Robotic Ethanol Inhibition Assays For Engineered Thermophilic Biofuel Strains, Kevin He, Daniel Olson, Marybeth Maloney, Anthony Lanahan

Wetterhahn Science Symposium Posters

Ethanol stress assays are commonly used to evaluate microbial tolerance, metabolic adaptation, and fermentation performance. However, manual liquid handling introduces variability across replicate wells and small-volume pipetting steps, limiting reproducibility and throughput. This study developed an automated OT-2 robotic workflow to generate replicated ethanol concentration gradients for high-throughput inhibition assays in engineered thermophilic biofuel strains. Kinetic plate-reader measurements were used to quantify ethanol-dependent growth responses under anaerobic fermentation conditions. The reasearch question is: How do engineered thermophilic biofuel strains differ in ethanol-dependent growth inhibition under anaerobic fermentation conditions, and can automated robotic assays improve the reproducibility of these measurements? Can …

Crystal Structure Of Mouse Dxo In Complex With The Udp-N-Acetylglucosamine Cap And Molecular Mechanism For The Decapping Reactions, Najeeb Ullah, Selom K. Doamekpor, Liang Tong

Department of Biochemistry and Molecular Biology Faculty Papers

Noncanonical metabolite 5' caps have recently been identified on RNAs, and the DXO/Rai1 family of enzymes can remove these caps in eukaryotes. While the binding modes of NAD, FAD and dephospho-CoA (dpCoA) caps in the active site of mouse DXO have been determined, how DXO recognizes the UDP-glucose (UDP-Glc) and UDP-N-acetylglucosamine (UDP-GlcNAc) caps is not known. In addition, the molecular mechanism by which DXO catalyzes the decapping reactions is still poorly understood, especially the location of the water/hydroxide that attacks the scissile phosphate to initiate the decapping. Here we report the crystal structure of mouse DXO in complex with UDP-GlcNAc …

Combating Β-Lactamase Resistance: From Inhibitor Design To Substrate Evolution, Lian M.C. Jacobs

USF Tampa Graduate Theses and Dissertations

β-lactamase production by bacteria is a major mechanism of antibiotic resistance. These enzymes hydrolyze β-lactam antibiotics, preventing them from binding to and inhibiting PBPs. Although new β-lactam scaffolds and inhibitors are continually introduced into the clinic, resistance often emerges within a few years. Therefore, the development of cross-class inhibitors with novel scaffolds is critical to mitigate this resistance. In parallel, a deeper understanding of the structural and mechanistic basis of β-lactamase resistance is essential. Together, these approaches provide an effective strategy for combating antibiotic resistance.

The first project addressed the need of effective cross-class β-lactamase inhibitors capable of targeting SBL …

In Vitro Reversal Of Abc Transporter Mediated Multidrug Resistance In Human Ovarian And Non-Small Cell Lung Cancer Models, Alison K. Kellom, Pia D. Vogel

Biological Sciences Theses and Dissertations

One of the major causes of treatment failure in aggressive cancers is multidrug resistance (MDR), which is linked to the overexpression of membrane efflux proteins that export chemotherapeutics from cancer cells. This mechanism prevents chemotherapeutic drugs from reaching cytotoxic concentrations intracellularly, allowing the cancer to survive. Two primary mediators of this mechanism are P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP). P-gp and BCRP are transmembrane ATP-binding cassette (ABC) transporters that are frequently overexpressed in MDR cancers. They utilize the binding and hydrolysis of ATP to transport a diverse range of amphipathic molecules of varying size (Schinkel and Jonker, 2003), …

Developing Antibodies Against Galectin-3 And Galectin-9 To Target Endometriosis, Ashleigh Burger, Noah Farnsworth, Jared J. Reisnouer, Cheyenne Vue

2026 Symposium

Endometriosis is a disease characterized by pelvic pain and the formation of endometrial-like tissue on the outside of the uterine lining. This condition affects nearly 10% of women across the globe and confirming whether someone has endometriosis requires visualization in surgery. While the specific causes of this disease remain unclear, the over-expression of the Galectins 3 and 9 in ectopic endometrial tissues suggests a role in the development and maintenance of the condition. Monoclonal antibodies (mAbs) are highly specific proteins with potential as diagnostic or treatment tools. The goal of this study is to generate antibodies against Gal3 and Gal9. …

Bax Activation Through The N-Terminal Bh3-Like Domains Of Vdac1 And Vdac2, Autumn A. Peters

Honors Theses

Voltage-dependent anion channels (VDACs) are central to mitochondrial function by mediating metabolite diffusion across the mitochondrial outer membrane (MOM). Two isoforms­­­­­­­­­­­,­­­­­­­­­­­­­­­­­­­­­­­­­­­­ VDACs 1 and 2, are also implicated in apoptosis based on interactions with Bcl-2 family proteins that control this process, including Bax and Bcl-xL. Activation of the pro-apoptotic protein Bax by interaction with ‘BH3-only’ proteins, such as Bim or Bid, induces MOM permeabilization to signal apoptosis, yet accumulating evidence indicates VDACs 1 and 2 may also affect Bax. We discovered that the VDAC N-terminal domains contain high sequence similarity to the conserved BH3 domains within Bcl-2 family members that …

Predicting And Decoding Allosteric Binding Sites Using Protein Language Models And Structure-Based Machine Learning: An Energy Landscape-Guided Explainable Ai Framework, Kamila Riedlová, Vít Skrhák, William G. Gatlin, Max Ludwick, Lucas Turano, Marian Novotný, David Hoksza, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

Computational prediction of allosteric binding sites in protein structures remains a persistent challenge, as these regulatory pockets evade detection by both sequence-based and structure-based algorithms. Both computational and physical origins of this predictive asymmetry remain insufficiently understood. In this study, we systematically examine the determinants of binding site predictability using a dual framework that integrates a fine-tuned protein language model and the structure-based method P2Rank as complementary tools probing a diverse data set of 453 human kinases, together with a physics-based interpretability layer derived from energy landscape frustration analysis. Both predictors exhibit a sharp and reproducible dichotomy on protein kinases, …