Genetics and Genomics Commons^™

The Role Of The Arched Helicases In Exosome-Mediated Function, A. Alejandra Klauer

Dissertations and Theses (Open Access)

RNA processing and degradation are two important functions that control gene expression and promote RNA fidelity in the cell. A major ribonuclease complex, called the exosome, is involved in both of these processes. The exosome is composed of ten essential proteins with only one catalytically active subunit, called Rrp44. While the same ten essential subunits make up both the nuclear and cytoplasmic exosome, there are nuclear and cytoplasmic exosome cofactors that promote specific exosome functions in each of the cell compartments. To date, it is unclear how the exosome distinguishes between RNA substrates. We hypothesize that compartment specific cofactors may …

Tet1: A Unique Dna Demethylase For Maintenance Of Dna Methylation Pattern, Chunlei Jin

Dissertations and Theses (Open Access)

DNA methylation at the C5 position of cytosine (5-methylcytosine, 5mC) is a crucial epigenetic modification of the genome and has been implicated in numerous cellular processes in mammals, including embryonic development, transcription, X chromosome inactivation, genomic imprinting and chromatin structure. Like histone modifications, DNA methylation is also dynamic and reversible. However, in contrast to well defined DNA methyltransferases, the enzymes responsible for erasing DNA methylation still remain to be studied. The ten-eleven translocation family proteins (TET1/2/3) were recently identified as Fe(II)/2-oxoglutarate (2OG)-dependent 5mC dioxygenases, which consecutively convert 5mC into 5-hydroxymethylcytosine (5hmC), 5-formylcytosine and 5-carboxylcytosine both in vitro and in mammalian …

A Genetic, Transgenic, And Transcriptomic Analysis Of Larval Salivary Gland Physiology In Drosophila Melanogaster, Elana A. Paladino

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cholesterol is the precursor to a unique class of lipophilic signaling molecules called steroid hormones that initiate the development of sexual characteristics, reactions to stress, and maintenance of metabolism, among many other functions. Although much progress has been made in understanding the function of these signaling hormones, we do not fully understand how a single steroid can cause many distinct, tissue-specific responses. Drosophila melanogaster is an effective model for understanding steroid hormone action because of its simplicity. The steroid molting hormone 20-hydroxyecdysone (hereafter, 20E) is the primary active steroid in Drosophila and mediates not only larval molts and the emergence …

Phylogeny And Evolutionary Patterns In The Dwarf Crayfish Subfamily (Decapoda: Cambarellinae), C. Pedraza-Lara, I. Doadrio, J. Breinholt, Keith A. Crandall

Computational Biology Institute

The Dwarf crayfish or Cambarellinae, is a morphologically singular subfamily of decapod crustaceans that contains only one genus, Cambarellus. Its intriguing distribution, along the river basins of the Gulf Coast of United States (Gulf Group) and into Central México (Mexican Group), has until now lacked of satisfactory explanation. This study provides a comprehensive sampling of most of the extant species of Cambarellus and sheds light on its evolutionary history, systematics and biogeography. We tested the impact of Gulf Group versus Mexican Group geography on rates of cladogenesis using a maximum likelihood framework, testing different models of birth/extinction of lineages. We …

Transcriptional Cross Talk Within The Mar-Sox-Rob Regulon In Escherichia Coli Is Limited To The Rob And Marrab Operons, Lon Chubiz, George Glekas, Christopher Rao

Biology Department Faculty Works

Bacteria possess multiple mechanisms to survive exposure to various chemical stresses and antimicrobial compounds. In the enteric bacterium Escherichia coli, three homologous transcription factors—MarA, SoxS, and Rob—play a central role in coordinating this response. Three separate systems are known to regulate the expression and activities of MarA, SoxS, and Rob. However, a number of studies have shown that the three do not function in isolation but rather are coregulated through transcriptional cross talk. In this work, we systematically investigated the extent of transcriptional cross talk in the mar-sox-rob regulon. While the three transcription factors were found to have the potential …

Insights Into Mrnp Biogenesis Provided By New Genetic Interactions Among Export And Transcription Factors, Francisco Estruch, Christine Hodge, Natalia Gómez-Navarro, Lorena Peiró-Chova, Catherine V. Heath, Charles N. Cole

Dartmouth Scholarship

The various steps of mRNP biogenesis (transcription, processing and export) are interconnected. It has been shown that the transcription machinery plays a pivotal role in mRNP assembly, since several mRNA export factors are recruited during transcription and physically interact with components of the transcription machinery. Although the shuttling DEAD-box protein Dbp5p is concentrated on the cytoplasmic fibrils of the NPC, previous studies demonstrated that it interacts physically and genetically with factors involved in transcription initiation. We investigated the effect of mutations affecting various components of the transcription initiation apparatus on the phenotypes of mRNA export mutant strains. Our results show …

Physiologically-Based Pharmacokinetic Modeling Of Acetaminophen Metabolism And Toxicity, David M. Ng, Ali Navid

STAR Program Research Presentations

Acetaminophen is a common analgesic and antipyretic. Metabolism of acetaminophen and acetaminophen-induced liver necrosis are predicted using physiologically-based pharmacokinetic (PBPK) modeling. Pharmacokinetic means the model determines where the drug is distributed in the body over time. Physiologically-based means the anatomy and physiology of the human body is reflected in the structure and functioning of the model. Acetaminophen is usually safe and effective when taken as recommended, but consumption at higher levels may lead to liver damage. Additionally, other factors such as alcoholic liver disease, smoking, and malnutrition affect the maximum safe dose of acetaminophen.

Selaginella Moellendorffii Telomeres: Conserved And Unique Features In An Ancient Land Plant Lineage, Eugene V. Shakirov, Dorothy E. Shippen

Biological Sciences Faculty Research

Telomeres, the essential terminal regions of linear eukaryotic chromosomes, consist of G-rich DNA repeats bound by a plethora of associated proteins. While the general pathways of telomere maintenance are evolutionarily conserved, individual telomere complex components show remarkable variation between eukaryotic lineages and even within closely related species. The recent genome sequencing of the lycophyte Selaginella moellendorffii and the availability of an ever-increasing number of flowering plant genomes provides a unique opportunity to evaluate the molecular and functional evolution of telomere components from the early evolving non-seed plants to the more developmentally advanced angiosperms. Here we analyzed telomere sequence in S. …

Mutation And Complementation Of A Cellulose Synthase (Cesa) Gene, Ahmed Y. El-Araby

Senior Honors Projects

Cellulose is a carbohydrate polymer that is composed of repeating glucose subunits. Being the most abundant organic compound in the biosphere and comprising a large percentage of all plant biomass, cellulose is extremely plentiful and has a significant role in nature. Cellulose is present in plant cell walls, in commercial products such as those made from wood or cotton, and is of interest to the biofuel industry as a potential alternative fuel source. Although indigestible by humans, cellulose is nutritionally valuable, serving as a dietary fiber. Because of its ubiquity and importance in many areas, studying cellulose will prove to …

Heterotopic Ossification: Cellular Basis, Symptoms, And Treatment, Brian Wolfe

Senior Honors Theses

Heterotopic ossification (HO) is the process by which calcified bone develops in soft tissues. Because of the abnormal calcification, complications such as bone deformation, loss of range of motion, and joint immobility adversely affect patients. There are many genetic types of heterotopic ossification, namely fibrodysplasia ossificans progressiva, progressive osseous heteroplasia, and Albright hereditary osteodystrophy. However, this condition can also arise from surgery, burns, or traumatic injuries, so it is seen as an important area for research in the future. There are various treatments available such as non-steroidal anti-inflammatory drugs and radiation therapy, as well as combinations of the two. The …

The Dietary Isoprenoid Perillyl Alcohol Inhibits Telomerase Activity In Prostate Cancer Cells, Tabetha Sundin

Theses and Dissertations in Biomedical Sciences

This is the first evidence that a plant-derived compound–perillyl alcohol regulates telomerase activity via the mammalian target of rapamycin (mTOR) pathway in prostate cancer cells. Telomerase–the enzyme responsible for immortalizing cells through telomeric repeats addition–is de-repressed early in an aspiring cancer cell. We hypothesized that perillyl alcohol regulates hTERT (human telomerase reverse transcriptase) at the translational and post-translational levels via its effects on the mTOR pathway. A rapid suppression of telomerase activity was detected in prostate cancer cell lines (PC-3 and DU145) in response to biologically-relevant concentrations and short incubations of perillyl alcohol or the mTOR inhibitor—rapamycin.

Western blot analysis …

Proteins: Form And Function, Roy D. Sleator

Department of Biological Sciences Publications

An overwhelming array of structural variants has evolved from a comparatively small number of protein structural domains; which has in turn facilitated an expanse of functional derivatives. Herein, I review the primary mechanisms which have contributed to the vastness of our existing, and expanding, protein repertoires. Protein function prediction strategies, both sequence and structure based, are also discussed and their associated strengths and weaknesses assessed.

Increased Variability Of Microbial Communities In Restored Salt Marshes Nearly 30 Years After Tidal Flow Restoration, Anne E. Bernhard, David Marshall, Lazaros Yiannos

Biology Faculty Publications

We analyzed microbial diversity and community composition from four salt marsh sites that were impounded for 40–50 years and subsequently restored and four unimpounded sites in southeastern Connecticut over one growing season. Community composition and diversity were assessed by terminal restriction fragment length polymorphism (TRFLP) and sequence analysis of 16S ribosomal RNA (rRNA) genes. Our results indicated diverse communities, with sequences representing 14 different bacterial divisions. Proteobacteria, Bacteroidetes, and Planctomycetes dominated clone libraries from both restored and unimpounded sites. Multivariate analysis of the TRFLP data suggest significant site, sample date, and restoration status effects, but the exact causes of these …

A Genomic Island In Salmonella Enterica Ssp. Salamae Provides New Insights On The Genealogy Of The Locus Of Enterocyte Effacement., P Scott Chandry, Simon Gladman, Sean C Moore, Torsten Seemann, Keith A Crandall, Narelle Fegan

Computational Biology Institute

The genomic island encoding the locus of enterocyte effacement (LEE) is an important virulence factor of the human pathogenic Escherichia coli. LEE typically encodes a type III secretion system (T3SS) and secreted effectors capable of forming attaching and effacing lesions. Although prominent in the pathogenic E. coli such as serotype O157:H7, LEE has also been detected in Citrobacter rodentium, E. albertii, and although not confirmed, it is likely to also be in Shigella boydii. Previous phylogenetic analysis of LEE indicated the genomic island was evolving through stepwise acquisition of various components. This study describes a new LEE region from two …

Mtbindingsim: Simulate Protein Binding To Microtubules, Julia T. Philip, Charles H. Pence, Holly V. Goodson

Faculty Publications

Summary: Many protein–protein interactions are more complex than can be accounted for by 1:1 binding models. However, biochemists have few tools available to help them recognize and predict the behaviors of these more complicated systems, making it difficult to design experiments that distinguish between possible binding models. MTBindingSim provides researchers with an environment in which they can rapidly compare different models of binding for a given scenario. It is written specifically with microtubule polymers in mind, but many of its models apply equally well to any polymer or any protein–protein interaction. MTBindingSim can thus both help in training intuition about …

The Role Of Chromatin And Cofactors In The Transcriptional Memory Effect Exerted In Saccharomyces Cerevisiae, Emily Leigh Paul

Legacy Theses & Dissertations (2009 - 2024)

Abf1 and Rap1 are functionally similar general regulatory factors (GRFs) found in Saccharomyces cerevisiae . Abf1, in its role as a transcriptional activator, exerts a memory effect on some genes under its control. This effect results in transcription levels remaining steady when Abf1 dissociates from its binding site in a conditional mutant. In contrast, Rap1 fails to elicit the same effect on its regulatory targets. Transcriptional memory effects have been observed in many fields of study, including immunology, cancer, and stem cells, and conservation of transcription machinery will allow studies in yeast to be applied to higher organisms.

The Role Of Ess1 In Survival, Morphogenetic Switching And Transcription In The Fungal Pathogen Candida Albicans, Dhanushki Poornima Samaranayake

Legacy Theses & Dissertations (2009 - 2024)

Candida albicans is a fungal pathogen that causes serious infections among immune-compromised patients and premature infants. C. albicans can become drug resistant, therefore, identifying new antifungal drug targets is an important goal. Here, we study a peptidyl-prolyl cis/trans isomerase called Ess1 as a potential drug target. Ess1 is conserved among pathogenic fungi, and therefore, potential inhibitors of Ess1 should display a broad spectrum of activity. We confirm that Ess1 is essential for growth in Candida albicans, but unlike the previously published find, deleting one copy of the C. albicans ESS1 gene did not affect morphogenetic switching. However, further reducing activity …

Mechanistic Studies Of A Novel Ppar-Gamma Mutant That Causes Lipodystrophy And Diabetes, Olga Astapova

Wayne State University Dissertations

PPAR-gamma is a nuclear receptor that plays a central role in metabolic regulation by regulating extensive gene expression networks in adipose, liver, skeletal muscle and many other tissues. Human PPAR-gamma mutations are rare and cause a monogenetic form of severe type II diabetes with metabolic syndrome, known as familiar partial lypodystrophy. The E157D PPAR-gamma mutant causes atypical lipodystrophy in a large Canadian kindred, presenting with multiple musculoskeletal, neurological and hematological abnormalities in addition to the classic lipodystrophy features of insulin-resistant diabetes, hypertension and dyslipidemia. This mutation is localized to the p-box of PPAR-gamma, a small region that interacts directly with …

Protein Structure Networks, Lesley H. Greene

Chemistry & Biochemistry Faculty Publications

The application of the field of network science to the scientific disciplines of structural biology and biochemistry, have yielded important new insights into the nature and determinants of protein structures, function, dynamics and the folding process. Advancements in further understanding protein relationships through network science have also reshaped the way we view the connectivity of proteins in the protein universe. The canonical hierarchical classification can now be visualized for example, as a protein fold continuum. This review will survey several key advances in the expanding area of research being conducted to study protein structures and folding using network approaches.

Expansion Dating: Calibrating Molecular Clocks In Marine Species From Expansions Onto The Sunda Shelf Following The Last Glacial Maximum, Eric D. Crandall, Elizabeth J. Sbrocco, Timery S. Deboer, Paul H. Barber, Kent E. Carpenter

Biological Sciences Faculty Publications

The rate of change in DNA is an important parameter for understanding molecular evolution and hence for inferences drawn from studies of phylogeography and phylogenetics. Most rate calibrations for mitochondrial coding regions in marine species have been made from divergence dating for fossils and vicariant events older than 1-2 My and are typically 0.5-2% per lineage per million years. Recently, calibrations made with ancient DNA (aDNA) from younger dates have yielded faster rates, suggesting that estimates of the molecular rate of change depend on the time of calibration, decaying from the instantaneous mutation rate to the phylogenetic substitution rate. aDNA …

Genetic Control Of A Central Pattern Generator: Rhythmic Oromotor Movement In Mice Is Controlled By A Major Locus Near Atp1a2, Steven J. St. John, John D. Boughter Jr, Megan K. Mulligan, Kenichi Tokita, Lu Lu, Detlef H. Heck, Robert W. Williams

Faculty Publications

calreticulin, Animals, Chromosome Mapping, Mammalian Chromosomes, Gene Expression Regulation, Genetic Linkage, Genome-Wide Association Study. Inbred C57BL Mice, Inbred DBA Mice, Quantitative Trait Loci, Sodium-Potassium-Exchanging ATPase/genetics, Atp1a2 protein, Sodium-Potassium-Exchanging ATPase, feeding behavior, drinking behavior, mice, central pattern generator, genetic control

Identification Of Cellular Functions Of Cardiolipin As Physiological Modifiers Of Barth Syndrome, Amit Shridhar Joshi

Wayne State University Dissertations

Cardiolipin (CL) is an anionic phospholipid synthesized in the mitochondrial inner membrane. Perturbation of CL metabolism leads to Barth syndrome (BTHS), a life threatening genetic disorder. I utilized genetic, biochemical and cell biological approaches in yeast to elucidate the cellular functions of CL. Understanding the functions of CL is expected to shed light on the pathology and possible treatments for BTHS.

BTHS is caused by mutations in TAZ1, which encodes a CL remodeling enzyme called tafazzin. BTHS patients exhibit a wide range of clinical presentations, indicating that physiological modifiers influence the BTHS phenotype. A targeted synthetic lethality screen was performed …

Global And Specific Controls Of Protein Synthesis In Hibernators, Peipei Pan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Mammalian hibernation is a highly dynamic physiological process that is composed of a series of torpor bouts, wherein hibernators oscillate between periods of torpor and interbout arousal. Although normally vital to homeostasis, many energetically consumptive processes such as translation or protein synthesis are virtually ceased during hibernation. Earlier studies indicated that protein synthesis had fallen to almost negligible levels. Cap-dependent initiation of translation is well regulated by eukaryotic translation initiation factor 4E (eIF4E) and its binding partner eIF4E-binding protein 1 (4E-BP1) when hibernators cycle in and out the torpor state. Herein, I investigated well-characterized regulatory mechanisms of global and specific …

Planning Combinatorial Disulfide Cross-Links For Protein Fold Determination, Fei Xiong, Alan M Friedman, Chris Bailey-Kellogg

Dartmouth Scholarship

Fold recognition techniques take advantage of the limited number of overall structural organizations, and have become increasingly effective at identifying the fold of a given target sequence. However, in the absence of sufficient sequence identity, it remains difficult for fold recognition methods to always select the correct model. While a native-like model is often among a pool of highly ranked models, it is not necessarily the highest-ranked one, and the model rankings depend sensitively on the scoring function used. Structure elucidation methods can then be employed to decide among the models based on relatively rapid biochemical/biophysical experiments.

Mitochondrial Dna Analysis By Denaturing High-Performance Liquid Chromatography For The Characterization And Separation Of Mixtures In Forensic Samples, Richard Kristinsson

Electronic Theses and Dissertations

A mixture of different mtDNA molecules in a single sample is a significant obstacle to the successful use of standard methods of mtDNA analysis (i.e., dideoxy dye-terminator sequencing). Forensic analysts often encounter either naturally occurring mixtures (e.g., heteroplasmy) or situational mixtures typically arising from a combination of body fluids from separate individuals. The ability to accurately resolve and interpret these types of samples in a timely and cost efficient manner would substantially increase the power of mtDNA analysis and potentially provide valuable investigative information by allowing its use in cases where the current approach is limited or fails. Therefore, this …

Investigating The Roles Of Ndj1 And Tid1 In Crossover Assurance In Saccharomyces Cerevisiae, Rianna Knowles

Master's Theses

Meiosis is the specialized process of cell division utilized during gametogenesis in all sexually reproducing eukaryotes, which consists of one round of DNA replication followed by two rounds of chromosome segregation and results in four haploid cells. Crossovers between homologous chromosomes promote proper alignment and segregation of chromosomes during meiosis.

Crossover interference is a genetic phenomenon in which crossovers are non-randomly placed along chromosomes. Crossover assurance ensures that every homologous chromosome pair obtains at least one crossover during Prophase I. Crossovers physically connect homologous pairs, allowing spindle fibers to attach and separate homologs properly. However, some organisms have shown an …

Mutant Alcohol Dehydrogenase Leads To Improved Ethanol Tolerance In Clostridium Thermocellum, Steven D. Brown, Adam M. Guss, Tatiana V. Karpinets, Jerry M. Parks

Dartmouth Scholarship

Clostridium thermocellum is a thermophilic, obligately anaerobic, Gram-positive bacterium that is a candidate microorganism for converting cellulosic biomass into ethanol through consolidated bioprocessing. Ethanol intolerance is an important metric in terms of process economics, and tolerance has often been described as a complex and likely multigenic trait for which complex gene interactions come into play. Here, we resequence the genome of an ethanol-tolerant mutant, show that the tolerant phenotype is primarily due to a mutated bifunctional acetaldehyde-CoA/alcohol dehydrogenase gene (adhE), hypothesize based on structural analysis that cofactor specificity may be affected, and confirm this hypothesis using enzyme assays. …

The Role Of A Transcription Factor In Regulating Rice Response To Drought Stress, Diana Ha, Liyuan A. Zhang, Jeffery Shen

Undergraduate Research Opportunities Program (UROP)

The current water shortage is a major concern in regard to our global climate change crisis. A decrease in the availability of water will have direct effects on the development of plants. Some crops, such as Oryza sativa, or commonly known as rice, requires an abundant amount of water for adequate growth. With the water shortage crisis, it will become extremely difficult to harvest such crops to meet the world’s food demand. However, many plants have evolved mechanisms for overcoming and tolerating stresses such as drought. My research focuses on studying the proteins involved with these mechanisms. The WRKY superfamily …

Inactivation Of Spo0a Gene Increases Stationary Phase Mutagenesis In Bacillus Subtilis, Denisse Reyes, Amanda Prisbrey, Holly Martin, Eduardo Robleto

Undergraduate Research Opportunities Program (UROP)

Stationary phase mutagenesis occurs when a population of cells acquires mutations conferring escape from nongrowing or stress conditions. This type of mutations is observed in nutritionally starved cells. Because the mutations occur after the onset of stress and in cells that are in non-replicative conditions, elucidating the underlying mechanisms contributes novel views to the process of evolution and apply to the formation of cancer in human cells and antibiotic resistance in microbial pathogens. Studies have shown that in Bacillus subtilis, the Mfd protein which is a transcription repair coupling factor is necessary for this phenomenon to occur. Here, we investigate …

Investigating The Origin Of Coprolites From Three Great Basin Caves, Chelsey Vandrisse, Duane P. Moser, David Rhode

Undergraduate Research Opportunities Program (UROP)

The study of coprolites (mummified feces) is a relatively new endeavor, which enables investigations of the health and diet of ancient people and provides some of the oldest evidence to date for the human habitation in North America (2). In this project, 18 coprolites were examined from archeological digs at three Great Basin caves: the Bonneville Estates Rockshelter (UT), Hidden Cave (NV), and Top of the Terrace Rockshelter (UT). The main objectives were: 1) to verify human origin through the presence of mitochondrial DNA (mtDNA) and 2) assuming human origin, characterize intestinal microflora of Native Americans prior to European contact. …