Molecular Biology Commons^™

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), …

Identification Of Covalent Catechin Adducts Of Enoyl-Acp Reductase (Fabi) From E. Coli Using Mass Spectrometry, Francisco G. Atwi, P. M. Joyner, Rustin Ghidari

Seaver College Research And Scholarly Achievement Symposium

Enoyl-ACP reductase (FabI), an enzyme which is inhibited by catechin, is essential for lipid biosynthesis in bacteria (E. coli). Another FabI inhibitor, triclosan, has strong antibacterial effects,1 but overuse can be detrimental to the environment. Flavonoids, a class of dietary compounds, are known to have potent inhibitory effects on FabI and other kinases.2,3,4 Adducts form as a result of the biochemical reaction between flavonoids and cysteine, a modification which can be verified by m/z shifts on the mass spectra.5 Samples of E. coli protein with overexpressed FabI are utilized: the wild type with ordinary primary structure, and mutant type lacking …

Patterns Of Ovarian And Gonadotropin Hormones In Emerging Adult Oral Contraceptive Users, Summer Mcormond

Undergraduate Research Posters

Oral contraceptives (OCs) are often initiated during adolescence and emerging adulthood, a period of continued maturation of the hypothalamic–pituitary–gonadal (HPG) axis. Because hormonal exposure during this window may shape emotional, biological, and reproductive outcomes, it is important to understand the specific formulations young women take and the hormonal profiles these formulations produce. This study characterizes OC formulation features and measured hormone levels in young adult OC users (n = 30).

Ethinyl estradiol (EE) doses ranged from 0.01–0.035 mg (mean = 0.022 mg), with 70% using ≤0.02 mg. Pill regimens included 21/7 packs (83%), 24/4 packs (10%), and 84/7 regimens (3%). …

Lighting Up The Cell: Developing A Luminescent Lanthanide Probe For Detecting Rnas, Jonathan Savell

Honors Projects

An anion detecting luminescent probe, Tb:DO2A-Cs124, was repurposed for use in RNA imaging. Potential RNA aptamers were identified for the molecule using Capture-SELEX and MinION sequencing. Fluorimetry data revealed these aptamers did not allow for the probe to luminesce in the presence of target RNAs due to adenosine monophosphate’s ability to quench the emission signal.

Domain Communication In Bifunctional Proline Utilization A From Sinorhizobium Meliloti, Emma Bitterman

Honors Program: Senior Projects (Public)

The reduction potential of flavin bound to Sinorhizobium meliloti proline utilization A (SmPutA) is beneficial in providing vital information on enzyme activity and the active site environment. Flavin is crucial in biological metabolism such as aerobic respiration and other important processes like oxygen activation that are catalyzed by flavin-dependent enzymes. (4). In this study, we seek to determine whether the redox potential of SmPutA-bound flavin can be used to characterize potential long-distance communication and analyze the possibilities of inactivation reversibility. SmPutA is a large bifunctional enzyme that catalyzes the overall oxidation of proline to glutamate via two catalytic domains (1). …

Predicting The Pathway Involvement Of Compounds Annotated In The Reactome Knowledgebase, Erik D. Huckvale, Hunter N. B. Moseley

Markey Cancer Center Faculty Publications

Background/Objectives: Pathway annotations of non-macromolecular (relatively small) biomolecules facilitate biological and biomedical interpretation of metabolomics datasets. However, low pathway annotation levels of detected biomolecules hinder this type of interpretation. Thus, predicting the pathway involvement of detected but unannotated biomolecules has a high potential to improve metabolomics data analysis and omics integration. Past publications have only made use of the Kyoto Encyclopedia of Genes and Genomes-derived datasets to develop machine learning models to predict pathway involvement. However, to our knowledge, the Reactome knowledgebase has not been utilized to develop these types of predictive models.

Methods: We created a dataset ready for …

Characterizing And Targeting The Non-Catalytic Functions Of Phosphatase Of Regenerating Liver 3 (Prl-3) In Oncogenesis And Cancer Progression, Jeffery T. Jolly

Theses and Dissertations--Molecular and Cellular Biochemistry

Phosphatase of Regenerating Liver 3 (PRL-3) is frequently upregulated in various cancers and is associated with poor patient prognosis. Although traditionally studied for its phosphatase activity, PRL-3 also interacts with the CNNM family of magnesium transporters through its catalytic site, and these two functions are mutually exclusive at any given time. Most previous studies relied on a commonly used PRL-3 mutation that disrupts both phosphatase activity and CNNM binding, making it challenging to determine which function drives its oncogenic effects. To address this gap in the field, I utilized a panel of PRL-3 mutants that selectively disrupt either phosphatase activity …

The Role Of Fbxl16 In Regulating Erk3 Stability And Cell Migration, Seth Charles Murdock

Browse all Theses and Dissertations

Extracellular signal-regulated kinase 3 (ERK3) is a member of the atypical mitogen-activated protein kinase (MAPK) family. While ERK3’s role in promoting cell migration and invasion in multiple types of cancer has been well-documented, its activation and regulation remain poorly understood. Unlike other typical MAPK proteins, whose activation is regulated via the phosphorylation of an upstream kinase, ERK3 is regulated through its abundance, as it is constitutively phosphorylated when present in the cell. While USP20 has been established as a deubiquitinating protein that stabilizes ERK3 by preventing its degradation, both TRIM21 and FBXW7 have been identified as E3 ligases that target …

Characterization Of The Erv41-Erv46 Complex As A Retrograde Receptor For Misfolded Secretory Proteins, John Andrew Fuesler

Dartmouth College Ph.D Dissertations

The Endoplasmic Reticulum (ER), the site of secretory protein biosynthesis

provides a favorable environment to promote polypeptide folding, protein

oligomerization and export. Although the ER contains many chaperones and other

factors that assist in protein folding, this process is error prone. Eukaryotes have

evolved protein quality control checkpoints to maintain homeostasis in the secretory

pathway, however these processes are imperfect and may result in proteotoxicity

when toxic levels or aggregates of proteins arise. Mutations in proteins involved in

trafficking in the early secretory pathway are closely associated with disease states.

Therefore, it is of great interest to further understand how …

Predicting The Association Of Metabolites With Both Pathway Categories And Individual Pathways, Erik D. Huckvale, Hunter Moseley

Markey Cancer Center Faculty Publications

Metabolism is a network of chemical reactions that sustain cellular life. Parts of this metabolic network are defined as metabolic pathways containing specific biochemical reactions. Products and reactants of these reactions are called metabolites, which are associated with certain human-defined metabolic pathways. Metabolic knowledgebases, such as the Kyoto Encyclopedia of Gene and Genomes (KEGG) contain metabolites, reactions, and pathway annotations; however, such resources are incomplete due to current limits of metabolic knowledge. To fill in missing metabolite pathway annotations, past machine learning models showed some success at predicting the KEGG Level 2 pathway category involvement of metabolites based on their …

Unveiling The Nexus Of Cellular Quality Control: Exploring The Interplay Between Ribosome-Associated Protein Quality Control And Mitochondrial Quality Control Pathways, Foozhan Tahmasebinia

Biological Sciences Theses and Dissertations

In eukaryotic cells, the intricate interplay between cellular quality control mechanisms is crucial for maintaining homeostasis and safeguarding the integrity of vital processes, spanning from macromolecule synthesis to the renewal of entire cellular organelles.

Disruption of these networks can lead to severe diseases such as metabolic disorders, underscoring the interconnected nature and feedback control mechanisms inherent in biological systems, including cellular quality control systems. This interconnectedness extends to the intricate communication between organelles, enabling coordinated functioning and adaptation to changing cellular conditions, particularly in response to stressors.

While the exact mechanisms governing these communications within cellular quality control systems remain …

Understanding The Non-Canonical Regulation Of Srebp In Aspergillus Fumigatus, Muhammad Abubakar Khan

Dartmouth College Ph.D Dissertations

Aspergillus fumigatus is an opportunistic fungal pathogen causing invasive pulmonary aspergillosis (IPA), with high mortality rates in immunocompromised individuals. Adaptation to the hypoxic microenvironment of IPA is crucial for fungal virulence. The transcription factor SrbA, a Sterol Regulatory Element-Binding Protein (SREBP) homolog, plays a key role in this hypoxic response and regulates genes involved in hypoxic growth, sterol biosynthesis, and azole resistance, making it an attractive therapeutic target.

However, SrbA activation in A. fumigatus lacks critical components of the canonical SREBP pathway, such as SCAP, Site-1 protease (S1P), and Site-2 protease (S2P). Instead, the rhomboid protease RbdB, signal peptide peptidase …

Long-Read Mdm4 Isoform Sequencing Reveals Aberrant Isoform Landscape In Metastatic Melanomas, Nehaal Rooha Patrick

Browse all Theses and Dissertations

The changes in splicing of MDM4 in human melanomagenesis are critical to p53 activity and represent potential therapeutic targets. Genomic characteristics of melanoma and precursor lesions, such as copy number variation and gene expression, have been investigated in detail. However, there has never been a detailed survey of splicing changes that occur during melanomagenesis. Splicing changes can be a very early event in melanoma tumor progression, with characteristic changes in the p53 pathway already in place in early nevi. MDM4 is upregulated in a strong majority of melanoma cases and has been described as a “key therapeutic target in cutaneous …

Hiv-1 Vpu Protein Forms Stable Oligomers In Aqueous Solution Via Its Transmembrane Domain Self-Association, Saman Majeed, Lan Dang, Md Majharul Islam, Olamide Ishola, Peter P Borbat, Steven J Ludtke, Elka R Georgieva

Faculty, Staff and Students Publications

We report our findings on the assembly of the HIV-1 protein Vpu into soluble oligomers. Vpu is a key HIV-1 protein. It has been considered exclusively a single-pass membrane protein. Previous observations show that this protein forms stable oligomers in aqueous solution, but details about these oligomers still remain obscure. This is an interesting and rather unique observation, as the number of proteins transitioning between soluble and membrane embedded states is limited. In this study we made use of protein engineering, size exclusion chromatography, cryoEM and electron paramagnetic resonance (EPR) spectroscopy to better elucidate the nature of the soluble oligomers. …

Regulation Of Erk3 By Kras Signalling And Its Role In The Growth Of Lung Adenocarcinoma (Luad) Cells, Shreya Akunapuram

Browse all Theses and Dissertations

Extracellular signal related kinase 3 (ERK3) is one of the atypical mitogen activated protein kinases (MAPK). It is expressed ubiquitously and plays a role in a variety of cellular processes, including cell growth and differentiation. ERK3’s role in promoting migration and invasion in various cancers has been well established. ERK3 is upregulated in non-small cell lung cancers (NSCLCs) and has been shown to promote NSCLC tumor growth and progression. However, the regulation of ERK3 in lung cancers remains largely unclear. A recent study indicates that ERK3 phosphorylation at S189, an indicator of ERK3 activity, is upregulated by KRAS in NSCLCs. …

Extension Of The Ergot Alkaloid Gene Cluster, Samantha Joy Fabian

Graduate Theses, Dissertations, and Problem Reports (ETD)

Specialized metabolites produced by fungi impact human health. A large portion of the pharmaceuticals currently on the market are derived from metabolites biosynthesized by microbes. Ergot alkaloids are a class of fungal metabolites that are important in the interactions of environmental fungi with insects and mammals and also are used in the production of pharmaceuticals. In animals, ergot alkaloids can act as partial agonists or antagonists at receptors for 5-hydroxytryptamine (serotonin), dopamine, and noradrenaline as ergot alkaloids have chemical structures similar to those neurotransmitters. Therefore, they affect insects and mammals that consume them and can be used to produce drugs …

The Effect Of Pomegranate Consumption On The Gut Microbiome, Brant Bandow

Browse all Theses and Dissertations

Pomegranate is known to have antioxidant and prebiotic qualities that have been shown to promote the growth of beneficial bacteria while reducing inflammation in the gut. Inflammation in the gut is an issue that results in many health problems including obesity and colon cancer. In this study, an experimental group received a daily pomegranate supplement for three weeks where a control group did not receive any supplement. After sequencing gDNA isolated from fecal samples from both before and after the trial period there was a significant difference between the two groups. The largest amount of variability is attributed to the …

A Novel Role Of Lipin1 In The Regulation Of Expression And Function Of Nnos, Ayat Azzam

Browse all Theses and Dissertations

Duchenne muscular dystrophy (DMD) is a severe and progressive muscular dystrophy that develops in the skeletal muscles because of mutations in the dystrophin gene. Dystrophin stabilizes sarcolemma and assembles neuronal nitric oxide synthase (nNOS) into the dystrophin-associated protein complex on the sarcolemma. The absence of dystrophin triggers the delocalization of nNOS and contributes to the misregulation of muscle development, blood flow, muscle fatigue, and inflammation. Lipin1 was reduced in the skeletal muscles of patients with DMD and the mdx mouse model of DMD. In this study, we explored the role of lipin1 in the regulation of nNOS expression and function. …

Functional Residues Of Cjpata, Robert Lamont

Theses and Dissertations (Comprehensive)

Antibiotic resistance in pathogenic bacteria continues to challenge clinicians and threaten the lives of infected individuals. For this reason, new classes of antibiotics or new targets for antibiotic therapy are needed to circumvent this global health crisis. In Gram-negative bacteria, the enzymes peptidoglycan O-acetyltransferase A and B (PatA and PatB), are responsible for adding acetyl groups to the C-6 hydroxyl group of N-acetyl muramic acid (MurNAc) in peptidoglycan (PG). These acetyl groups are responsible for inhibiting the activity of lysozyme from host organisms that hydrolyze the β1-4 glycosidic linkage between MurNAc and N-acetylglucosamine (GlcNAc). The acetyl groups …

Molecular Characterization Of Nitrogenase Regulation In Methanosarcina Acetivorans, Melissa Chanderban

Graduate Theses and Dissertations

Nitrogenase is the metalloenzyme only found in bacteria and archaea that is essential for biological nitrogen fixation (diazotrophy), but it can also serve as a catalyst in biofuel production. All diazotrophs contain a molybdenum (Mo) nitrogenase, while some species contain additional alternative nitrogenases where either vanadium (V) or iron (Fe) replace Mo in the active site cofactor. Nitrogen fixation by bacteria has been extensively studied. The limited investigation of nitrogen fixation in methanogenic archaea (methanogens) indicates production of nitrogenase is simpler than in bacteria and methanogen nitrogenase has different biochemical properties. Thus, methanogen nitrogenases provide a promising alternative for genetic …

Assembly Of The Peripheral Arm Subunits Of Escherichia Coli Complex I And Analysis Of Clinical Mutations, Hind Alkhaldi

Biological Sciences Theses and Dissertations

Respiratory Complex I from E. coli is a proto-type of the mitochondrial enzyme, consisting of a 6-subunit peripheral arm (B-CD-E-F-G-I) and a 7-subunit membrane arm. When subunits E-F-G (N-module), were expressed alone they formed an active complex as determined by co-immunoprecipitation and native gel electrophoresis. When co-expressed with subunits B and CD, only a complex of E-F-G was found. When these five subunits were co-expressed with subunit I and two membrane subunits, A and H, a complex of B-CD-E-F-G-I was membrane-bound, constituting the N- and Q-modules. Assembly of Complex I was also followed by splitting the genes between two plasmids, …

Mechanisms Of Telomere Maintenance In Trypanosoma Brucei, M A G G. Rabbani

ETD Archive

Telomeres are a nucleoprotein structure at the end of the chromosome and are essential for genome integrity and chromosome stability. Telomere lengths are primarily maintained by a telomerase-mediated pathway but can be maintained by a homologous recombination-mediated pathway. However, detailed mechanisms of telomere maintenance are still unclear in many eukaryotes, including an important human pathogen, Trypanosoma brucei. Telomeres can be elongated by telomerase in T. brucei, a causative agent of fatal sleeping sickness in humans and nagana in cattle. T. brucei evades host immune response by regularly switching its major surface antigen, variant surface glycoprotein (VSG), a process known as …

Multicopy Suppression Of Ribosomal Protein Deletion Mutants, Jacqualine Cerbone

Senior Honors Projects

To suppress the ribosome assembly defective phenotype of a ribosomal protein uS17- deficient mutant, various ribosomal proteins were used to act as multicopy suppressors. Ribosomal protein uS17 is a highly conserved component of the 30S (small) ribosomal subunit and is important for 30S subunit assembly. Mutants with a deletion of rpsQ (the gene encoding uS17) are viable but have a severe 30S subunit assembly defect and a temperature-sensitive (ts) phenotype. While fully assembled 30S subunits do form, incomplete ("20S") particles lacking several proteins accumulate. We hypothesized that increasing the intracellular concentration of one or more of the proteins missing from …

Establishing A Biochemical System For The Purification And Atpase Activity Of Gst-Dbp5, Sarah R. Utley, Rachel E. Rigsby Phd, Rebecca L. Adams Phd

Science University Research Symposium (SURS)

The export of mRNA out of the nucleus is a crucial step for eukaryotic gene expression. The export of mRNA transcripts is aided by Mex67, which allows export through the nuclear pore complex doorways in the nuclear envelope. Once out of the nucleus, a protein known as Dbp5, bound to ATP, Gle1, and Nup42 aids in the directionality of mRNA export by helping remove Mex67 from the mRNA strand. Following interaction with RNA, Dbp5 then hydrolyzes ATP so that it unbinds the mRNA, allowing for enzyme recycling. Previous efforts worked towards the purification of Dbp5, but the attempts were unsuccessful …

Genomic Instability At A Polypurine/Polypyrimidine Repeat Sequence, Nathen S. Zavada

Browse all Theses and Dissertations

Microsatellite repeat sequences have been shown to induce replication stalling, fork collapse, double-strand breaks (DSBs), and possibly stimulate break-induced replication. In this study we use a dual-fluorescent HeLa model that is designed to monitor recombination at an ectopic site through use of flow cytometry and inverse PCR with a microsatellite in the lagging strand for DNA synthesis. To test the stability of the 78 bp polypurine/pyrimidine repeat from the PDK1 locus, we subjected cells to replication stress drugs designed to induce DSBs and measure break-induced replication (BIR). The study revealed that polypurine repeat cells undergo endogenous stress contributing to instability …

Instability And Extrachromosomal Circular Dna Formation At Microsatellites And Unstable Dna Sequences, Matilyn M. Shanahan

Browse all Theses and Dissertations

We have previously documented our evidence of genetic instabilities at the (Pu/Py)78 and (ATTCT)47 sequences and our reasoning for identifying break-induced replication (BIR) as the mode of repair responsible for the mutations in the DNA flanking the unstable inserts. Now, as our lab investigates the protein mechanisms at play in the BIR pathway taking place at these sites, we are also expanding our knowledge of how this mechanism extends into the pathways responsible for forming extrachromosomal circular DNA (eccDNA) molecules. We have documented the phenomena posed as the driving factors for eccDNA formation in our systems containing (Pu/Py)78 and (ATTCT)47. …

Effects Of Lipin1 Deficiency & Restoration In The Dystrophic Diaphragm, Alexandra Brown

Browse all Theses and Dissertations

Duchenne Muscular Dystrophy (DMD) is an X-linked recessive disorder that is characterized by severe and progressive muscle wasting (Venugopal & Pavlakis, 2021). This disease is caused by a mutation in the largest known human gene which encodes the protein, dystrophin (Gao & McNally, 2015). Dystrophin connects the inner cytoskeleton to the extracellular matrix and is critical for maintaining the structural stability of muscle cells during contraction (Venugopal & Pavlakis, 2021). Mutations to the dystrophin gene result in myocyte membrane instability, contributing to the structural deterioration of the muscle tissue (Venugopal & Pavlakis, 2021). Progressive muscle degeneration and the replacement of …

The Role Of Pi4kb In Cellular Localization Of Small Gtpases, Parisa Sadrpour

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Constitutively active oncogenic mutant K-Ras is one the principal contributors to human cancers including 90% of pancreatic, 50% of colorectal and 32% of non-small cell lung cancers. However, except for K-Ras G12C oncogenic mutant, which only presents in about 13% of non-small cell lung cancer patients, there is no anti-K-Ras therapy for a considerable subset of K-Ras mutations in human tumors, reflecting challenges for targeting oncogenic K-Ras activity. K-Ras is a membrane-bound small GTPase; when active, it triggers multiple signaling pathways regulating a variety of key cellular functions such as cell growth, proliferation and survival. To initiate these signaling cascades, …

Investigation Of A Carbon Monoxide Dehydrogenase From An Uncultured Archaeon, Luke Moore

Dissertations, Master's Theses and Master's Reports

The Nickel based Carbon Monoxide Dehydrogenase (CODH) is an anaerobic metalloenzyme responsible for the reversible conversion of CO and water into CO2 and 2 protons and 2 electrons. This enzyme has importance in the environment as one of Earth’s first carbon fixation pathways, and for human uses as a potential source of biofuels and other commodity chemicals. CODH enzymes are present in a wide array of taxa, many of which are uncultured. In this study we express and purify the catalytic subunit (CooS) of the anaerobic CODH from an uncultured Hydrothermarchaeota JdFR-17 co-expressed with the nickel insertion accessory protein (CooC) …

Molecular Mechanisms Of Aberrant Protein Glycosylation In Pancreatic Cancer Stemness And Metastasis, Frank Leon

Theses & Dissertations

A myriad of genetic and other abnormal changes underlies the aggressiveness and dissemination properties observed in pancreatic cancer (PC). Aberrant protein glycosylation is a commonly observed feature in PC. The modification of protein O-glycosylation is mediated by glycosyltransferases, which attach and sequentially elongate monosaccharides on Serine/Threonine (Ser/Thr) motifs. Aberrant glycosylation is recognized as an emerging hallmark of cancer where a disruption in normal glycosylation results in irregular O-glycans.

This dissertation research has investigated the consequences of aberrant protein glycosylation on stemness and enhancement of metastatic properties in pancreatic ductal adenocarcinoma (PDAC). Several publications have reported aberrant O-glycosylation increases in oncogenic …