Molecular Biology Commons^™

Expansin Synergy With Cellulases: Development Of A Transgenic Maize System For Expansin Production And Evaluation Of Synergistic Activity On Lignocellulosic Substrates, Sangwoong Yoon

Student Theses and Dissertations

One of the greatest barriers to produce biofuels from lignocellulosic material is efficient cellulose depolymerization by cellulase activity. Expansin is a protein that is active in cell wall expansion in growing regions of most plants. Because of this unique activity, expansin synergistic activity with cellulase is believed to lower the depolymerization barrier. Over-expression of expansin in the maize production system is designed to produce sufficient protein 1) to study its physiological effects, and 2) to assess its ability to serve as an industrial enzyme for applications, particularly in biomass conversion. Transgenic lines of maize that express the cucumber expansin gene …

Cloning, Expression, And Characterization Of Ara H 3, A Major Peanut Allergen, Cathryn E. Garvey

LSU New Orleans Theses and Dissertations

Abstract There are eight foods that contribute to food allergies in the western world and peanut is the most common. Currently, there are no medical treatments that can cure an individual of food allergy, so avoidance of the allergic food is the only option. In the United States, there are three immunodominant allergic proteins accountable for patient sensitization to peanut, Arachis hypogea 1, 2, and 3 (Ara h 1, Ara h 2, Ara h 3). Therefore, research into why peanuts are more allergic than other foods that have homologous proteins is critical and may be obtained by studying the structural …

Selection Of Trna Charging Quality Control Mechanisms That Increase Mistranslation Of The Genetic Code, Srujana S. Yadavalli, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Mistranslation can follow two events during protein synthesis: production of non-cognate amino acid:transfer RNA (tRNA) pairs by aminoacyl-tRNA synthetases (aaRSs) and inaccurate selection of aminoacyl-tRNAs by the ribosome. Many aaRSs actively edit non-cognate amino acids, but editing mechanisms are not evolutionarily conserved, and their physiological significance remains unclear. To address the connection between aaRSs and mistranslation, the evolutionary divergence of tyrosine editing by phenylalanyl-tRNA synthetase (PheRS) was used as a model. Certain PheRSs are naturally error prone, most notably a Mycoplasma example that displayed a low level of specificity consistent with elevated mistranslation of the proteome. Mycoplasma PheRS was found …

Molecular Mechanisms Regulating Neonatal Oocyte Survival And Primordial Follicle Formation In The Mouse Ovary, Robin L. Jones

Biology - Dissertations

In mammals, formation of the primordial follicle is a complex process involving the breakdown of germ cell cysts, where oocytes must separate from each other and subsequently become surrounded by somatic cells. As cysts separate, a large number of germ cells are lost by apoptosis, however the mechanisms by which cyst breakdown and germ cell death occur are not well understood. We first hypothesized that two anti-apoptotic regulators from the BCL2 family of proteins, BCL2 and MCL1, may be responsible for regulating neonatal oocyte survival. To elucidate the effects of BCL2 in the neonatal ovary, we examined ovaries of both …

Secondary Structure, A Missing Component Of Sequence- Based Minimotif Definitions, David P. Sargeant, Michael R. Gryk, Mark W. Maciejewsk, Vishal Thapar, Vamsi Kundeti, Sanguthevar Rajasekaran, Pedro Romero, Keith Dunker, Shun-Cheng Li, Tomonori Kaneko, Martin Schiller

Life Sciences Faculty Research

Minimotifs are short contiguous segments of proteins that have a known biological function. The hundreds of thousands of minimotifs discovered thus far are an important part of the theoretical understanding of the specificity of protein-protein interactions, posttranslational modifications, and signal transduction that occur in cells. However, a longstanding problem is that the different abstractions of the sequence definitions do not accurately capture the specificity, despite decades of effort by many labs. We present evidence that structure is an essential component of minimotif specificity, yet is not used in minimotif definitions. Our analysis of several known minimotifs as case studies, analysis …

Characterization And Epidemiology Of Soybean Vein Necrosis Associated Virus, Jing Zhou

Graduate Theses and Dissertations

Soybean vein necrosis disease (SVND) is widespread in major soybean-producing areas in the U.S. The typical disease symptoms exhibit as vein clearing along the main vein, which turn into chlorosis or necrosis as season progresses. Double-stranded RNA isolation and shot gun cloning of symptomatic tissues revealed the presence of a new tospovirus, provisionally named as Soybean vein necrosis associated virus (SVNaV). The presence of the virus has been confirmed in 12 states: Arkansas, Illinois, Missouri, Kansas, Tennessee, Kentucky, Mississippi, Maryland, Delaware, Virginia and New York. Symptomatic samples collected from eight states (AR, IL, MO, MS, KS, TN, MD and DE), …

The Role Of Centromeric Chromatin And Kinetochore-Associated Factors In Chromosome Segregation, Wesley Williamson

Graduate Theses and Dissertations

Previous work in our lab has identified a point mutation in HTA1, one of the genes encoding histone H2A, which causes an increase-in-ploidy phenotype in Saccharomyces cerevisiae. This histone mutant strain was used to carry out a transposon insertion screen to identify suppressors of the increase-in-ploidy phenotype. This screen identified all three subunits of the Hda histone deacetylase complex, HDA1, HDA2, and HDA3. This study aims to elucidate the function of the Hda complex in chromosome segregation by exploring interactions among the members of the complex, as well as interactions between Hda complex and kinetochore components. …

A Study On The Function Of 14-3-3sigma In Regulating Cancer Energy Metabolism, Liem M. Phan, Liem M. Phan

Dissertations and Theses (Open Access)

Metabolic reprogramming has been shown to be a major cancer hallmark providing tumor cells with significant advantages for survival, proliferation, growth, metastasis and resistance against anti-cancer therapies. Glycolysis, glutaminolysis and mitochondrial biogenesis are among the most essential cancer metabolic alterations because these pathways provide cancer cells with not only energy but also crucial metabolites to support large-scale biosynthesis, rapid proliferation and tumorigenesis. In this study, we find that 14-3-3σ suppresses all these three metabolic processes by promoting the degradation of their main driver, c-Myc. In fact, 14-3-3s significantly enhances c-Myc poly-ubiquitination and subsequent degradation, reduces c-Myc transcriptional activity, and down-regulates …

The Role Of Hsc-70 In Very Low Density Lipoprotein Tranport Vesicle Golgi Fusion Complex Formation, Erika Nafi Valencia

HIM 1990-2015

Excess production and secretion of very low-density lipoprotein (VLDL) by the liver into the circulatory system is directly related to atherosclerosis, a chronic cardiovascular disease that threatens the lives of many worldwide and continues to be a leading cause of death in the United States. The rate-limiting step in VLDL secretion is its transport from the site of biogenesis, the hepatic endoplasmic reticulum to the cis-Golgi. This step is mediated by a specialized ER- derived vesicle, the VLDL transport vesicle (VTV). Upon exit of the ER the VTV targets, fuses and delivers VLDL into the lumen of the Golgi. The …

Functional Analysis Of Drosophila Integrator Complex In Snrna 3' End Processing, Jiandong Chen

Dissertations and Theses (Open Access)

Uridine-rich small nuclear RNAs (U snRNAs) play essential roles in eukaryotic gene expression by facilitating the removal of introns from mRNA precursors and the processing of the replication-dependent histone pre-mRNAs. Formation of the 3’ end of these snRNAs is carried out by a poorly characterized, twelve-membered protein complex named Integrator Complex.

In the effort to understand Integrator Complex function in the formation of the snRNA 3’ end, we performed a functional RNAi screen in Drosophila S2 cells to identify protein factors required for snRNA 3’ end formation. This screen was conducted by using a fluorescence-based reporter that elicits GFP expression …

Structure-Function Analysis Of A Protein Encoded By The Bhv-1 Latency Related Gene, Devis Sinani

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Bovine herpes virus 1 (BHV-1) is a significant viral pathogen in cattle that induces a myriad of clinical symptoms. These symptoms include: conjunctivitis, upper respiratory tract infections, genital disorders, and abortions. BHV-1 infection can also lead to transient immune-suppression, which predisposes cattle to secondary bacterial infection leading to life-threatening pneumonia referred to as bovine respiratory disease (BRD). Following acute infection, BHV-1 establishes latency in sensory neurons within trigeminal ganglia. Reactivation of the virus can occur periodically, resulting in virus transmission. The latency-related (LR) RNA is the only abundantly expressed transcript in latently infected sensory neurons and it encodes several proteins, …

Fancm And Faap24 Maintain Genomic Stability Through Cooperative And Unique Functions, Yucai Wang

Dissertations and Theses (Open Access)

Fanconi anemia (FA) is a rare recessive genetic disease with an array of clinical manifestations including multiple congenital abnormalities, progressive bone marrow failure and profound cancer susceptibility. A hallmark of cells derived from FA patients is hypersensitivity to DNA interstrand crosslinking agents such as mitomycin C (MMC) and cisplatin, suggesting that FA- and FA-associated proteins play important roles in protecting cells from DNA interstrand crosslink (ICL) damage. Two genes involved in the FA pathway, FANCM and FAAP24, are of particular interest because they contain DNA interacting domains. However, there are no definitive patient mutations for these two genes, and the …

Differential Activity Of The Kras Oncogene By Method Of Activation: Implications For Signaling And Therapeutic Intervention, Nathan Ihle

Dissertations and Theses (Open Access)

Despite having been identified over thirty years ago and definitively established as having a critical role in driving tumor growth and predicting for resistance to therapy, the KRAS oncogene remains a target in cancer for which there is no effective treatment. KRas is activated b y mutations at a few sites, primarily amino acid substitutions at codon 12 which promote a constitutively active state. I have found that different amino acid substitutions at codon 12 can activate different KRas downstream signaling pathways, determine clonogenic growth potential and determine patient response to molecularly targeted therapies. Computer modeling of the KRas structure …

Trim24-Regulated Estrogen Response Is Dependent On Specific Histone Modifications In Breast Cancer Cells, Teresa T. Yiu

Dissertations and Theses (Open Access)

In this dissertation, I discovered that function of TRIM24 as a co-activator

of ERα-mediated transcriptional activation is dependent on specific histone

modifications in tumorigenic human breast cancer-derived MCF7 cells. In the first

part, I proved that TRIM24-PHD finger domain, which recognizes unmethylated

histone H3 lysine K4 (H3K4me0), is critical for ERα-regulated transcription.

Therefore, when LSD1-mediated demethylation of H3K4 is inhibited, activation of

TRIM24-regulated ERα target genes is greatly impaired. Importantly, I

demonstrated that TRIM24 and LSD1 are cyclically recruited to estrogen

responsive elements (EREs) in a time-dependent manner upon estrogen

induction, and depletion of their expression exert corresponding time-dependent

effect …

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 …

Characterization Of Beryllium As A Novel Agent To Study Cell Cycle Arrest And Cellular Senescence, Priyatham Gorjala

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cancer cells evade senescence, apoptosis, and other constraints on proliferation, often via mutation of the p53 tumor suppressor gene (TP53). Normal human lung fibroblasts have been shown to enter premature senescence upon exposure to beryllium. In these cells, BeSO₄ stabilizes p53 protein, increases p21 gene expression, induces senescence-associated β-galactosidase activity and causes cell proliferation arrest. In the present study, we have investigated whether BeSO₄ is able to induce similar effects in cancer cells that have wildtype p53. We have demonstrated that beryllium salt at low concentration can induce molecular changes in the p53 signaling pathway leading to cell …

Differential Effects Of The Hydrophobic Surfactant Proteins On The Formation Of Inverse Bicontinuous Cubic Phases, Mariya Chavarha, Ryan W. Loney, Kamlesh Kumar, Shankar B. Rananavare, Stephen B. Hall

Chemistry Faculty Publications and Presentations

Prior studies have shown that the biological mixture of the two hydrophobic surfactant proteins, SP-B and SP-C, produces faster adsorption of the surfactant lipids to an air/water interface, and that they induce 1-palmitoyl-2-oleoyl phosphatidylethanolamine (POPE) to form inverse bicontinuous cubic phases. SP-B has a much greater effect than SP-C on adsorption. If the two proteins induce formation of the bicontinuous structures and faster adsorption by similar mechanisms, then they should also have differential ability to form the cubic phases. To test this hypothesis, we measured small angle X-ray scattering on the individual proteins combined with POPE. SP-B replicated the doserelated …

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 …

Achieving High Accuracy Prediction Of Minimotifs, Tian Mi, Sanguthevar Rajasekaran, Jerlin Camilus Merlin, Michael R. Gryk, Martin Schiller

Life Sciences Faculty Research

The low complexity of minimotif patterns results in a high false-positive prediction rate, hampering protein function prediction. A multi-filter algorithm, trained and tested on a linear regression model, support vector machine model, and neural network model, using a large dataset of verified minimotifs, vastly improves minimotif prediction accuracy while generating few false positives. An optimal threshold for the best accuracy reaches an overall accuracy above 90%, while a stringent threshold for the best specificity generates less than 1% false positives or even no false positives and still produces more than 90% true positives for the linear regression and neural network …

Sex Determination In Beetles: Production Of All Male Progeny By Parental Rnai Knockdown Of Transformer, Jayendra Nath Shukla, Subba Reddy Palli

Entomology Faculty Publications

Sex in insects is determined by a cascade of regulators ultimately controlling sex-specific splicing of a transcription factor, Doublesex (Dsx). We recently identified homolog of dsx in the red flour beetle, Tribolium castaneum (Tcdsx). Here, we report on the identification and characterization of a regulator of Tcdsx splicing in T. castaneum. Two male-specific and one female-specific isoforms of T. castaneum transformer (Tctra) were identified. RNA interference-aided knockdown of Tctra in pupa or adults caused a change in sex from females to males by diverting the splicing of Tcdsx pre-mRNA to male-specific isoform. All the pupa and adults developed from Tctra …