Medicine and Health Sciences Commons^™

A Novel Runx2 Missense Mutation Predicted To Disrupt Dna Binding Causes Cleidocranial Dysplasia In A Large Chinese Family With Hyperplastic Nails, Shaohua Tang, Qiyu Xu, Xueqin Xu, Jicheng Du, Xuemei Yang, Yusheng Jiang, Xiaoqin Wang, Nancy Speck, Taosheng Huang

Dartmouth Scholarship

Background: Cleidocranial dysplasia (CCD) is a dominantly inherited disease characterized by hypoplastic or absent clavicles, large fontanels, dental dysplasia, and delayed skeletal development. The purpose of this study is to investigate the genetic basis of Chinese family with CCD.

Methods: Here, a large Chinese family with CCD and hyperplastic nails was recruited. The clinical features displayed a significant intrafamilial variation. We sequenced the coding region of the RUNX2 gene for the mutation and phenotype analysis.

Results: The family carries a c.T407C (p.L136P) mutation in the DNA- and CBFβ-binding Runt domain of RUNX2. Based on the crystal structure, we predict this …

Repeated N-Acetylcysteine Administration Alters Plasticity-Dependent Effects Of Cocaine, Aric Madayag, Doug Lobner, Kristen S. Kau, John R. Mantsch, Omer Abdulhameed, Matthew Hearing, Mark D. Grier, David A. Baker

Biomedical Sciences Faculty Research and Publications

Cocaine produces a persistent reduction in cystine–glutamate exchange via system x_c− in the nucleus accumbens that may contribute to pathological glutamate signaling linked to addiction. System x_c− influences glutamate neurotransmission by maintaining basal, extracellular glutamate in the nucleus accumbens, which, in turn, shapes synaptic activity by stimulating group II metabotropic glutamate autoreceptors. In the present study, we tested the hypothesis that a long-term reduction in system x_c− activity is part of the plasticity produced by repeated cocaine that results in the establishment of compulsive drug seeking. To test this, the cysteine prodrug N-acetylcysteine …

Oral Immunization Of Rhesus Macaques With Adenoviral Hiv Vaccines Using Enteric-Coated Capsules, George T. Mercier, Pramod N. Nehete, Marco F. Passeri, Bharti N. Nehete, Eric A. Weaver, Nancy Smyth Templeton, Kimberly Schluns, Stephanie S. Buchl, K. Buchl, Michael A. Barry

Nebraska Center for Virology: Faculty Publications

Targeted delivery of vaccine candidates to the gastrointestinal (GI) tract holds potential for mucosal immunization, particularly against mucosal pathogens like the human immunodeficiency virus (HIV). Among the different strategies for achieving targeted release in the GI tract, namely the small intestine, pH sensitive enteric coating polymers have been shown to protect solid oral dosage forms from the harsh digestive environment of the stomach and dissolve relatively rapidly in the small intestine by taking advantage of the luminal pH gradient. We developed an enteric polymethacrylate formulation for coating hydroxy-propyl-methyl-cellulose (HPMC) capsules containing lyophilized Adenoviral type 5 (Ad5) vectors expressing HIV-1 gag …

Direct Inhibition Of Cdk9 Blocks Hiv-1 Replication Without Preventing T Cell Activation In Primary Human Peripheral Blood Lymphocytes, Dominic Salerno, Muneer G Hasham, Renée Marshall Demarest, Judit Garriga, Alexander Y Tsygankov, Xavier Graña

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

HIV-1 transcription is essential for the virus replication cycle. HIV-1 Tat is a viral transactivator that strongly stimulates the processivity of RNA polymerase II (RNAPII) via recruitment of the cyclin T1/CDK9 positive transcription elongation factor, which phosphorylates the C-terminal domain (CTD) of RNAPII. Consistently, HIV-1 replication in transformed cells is very sensitive to direct CDK9 inhibition. Thus, CDK9 could be a potential target for anti-HIV-1 therapy. A clearer understanding of the requirements for CDK9 activity in primary human T cells is needed to assess whether the CDK9-dependent step in HIV-1 transcription can be targeted clinically. We have investigated the effects …

A Developmental Cycle Masks Output From The Circadian Oscillator Under Conditions Of Choline Deficiency In Neurospora, Mi Shi, Luis F. Larrondo, Jennifer J. Loros, Jay C. Dunlap

Dartmouth Scholarship

In Neurospora, metabolic oscillators coexist with the circadian transcriptional/translational feedback loop governed by the FRQ (Frequency) and WC (White Collar) proteins. One of these, a choline deficiency oscillator (CDO) observed in chol-1 mutants grown under choline starvation, drives an uncompensated long-period developmental cycle ( approximately 60-120 h). To assess possible contributions of this metabolic oscillator to the circadian system, molecular and physiological rhythms were followed in liquid culture under choline starvation, but these only confirmed that an oscillator with a normal circadian period length can run under choline starvation. This finding suggested that long-period developmental cycles elicited by nutritional stress …

Light-Evoked Calcium Responses Of Isolated Melanopsin- Expressing Retinal Ganglion Cells, Andrew T. E. Hartwick, Jayne R. Bramley, Jianing Yu, Kelly T. Stevens, Charles N. Allen, William H. Baldridge, Patricia J. Sollars, Gary E. Pickard

School of Veterinary and Biomedical Sciences: Faculty Publications

A small number (<2%) of mammalian retinal ganglion cells express the photopigment melanopsin and are intrinsically photosensitive (ipRGCs). Light depolarizes ipRGCs and increases intracellular calcium levels ( [Ca²⁺]_i ) but the signaling cascades underlying these responses have yet to be elucidated. To facilitate physiological studies on these rare photoreceptors, highly enriched ipRGC cultures from neonatal rats were generated using anti-melanopsin-mediated plate adhesion (immunopanning). This novel approach enabled experiments on isolated ipRGCs, eliminating the potential confounding influence of rod/cone-driven input. Light induced a rise in [Ca²⁺]_i (monitored using fura-2 imaging) in the immunopanned ipRGCs and the source of this Ca²⁺ signal was investigated. The Ca²⁺ responses were inhibited by 2-aminoethoxydiphenyl borate, SKF-96365 (1–2-(4-methoxyphenyl)-2-[3-(4-methoxyphenyl)propoxy]ethyl-1H-imidazole), flufenamic acid, …

Dietary Canola Oil Suppressed Growth Of Implanted Mda-Mb 231 Human Breast Tumors In Nude Mice, W. Elaine Hardman

Biochemistry and Microbiology

Long chain omega 3 (n-3) fatty acids, eicosapentaenoic (EPA) and/or docosahexaenoic acid (DHA), have been shown to suppress growth of most cancer cells. In vivo, alpha linolenic acid (ALA, 18:3n-3) can be converted to EPA or DHA. We hypothesized that substituting canola oil (10% ALA) for the corn oil (1% ALA) in the diet of cancer bearing mice would slow tumor growth by increasing n-3 fatty acids in the diet. Sixty nude mice received MDA-MB 231 human breast cancer cells and were fed a diet containing 8% w/w corn oil until the mean tumor volume was 60 mm ³ . …

A Novel Inhibitory Mechanism Of Mitochondrion-Dependent Apoptosis By A Herpesviral Protein, Pinghui Feng, Chengyu Liang, Young C. Shin, Xiaofei E, Weijun Zhang, Robyn Gravel, Ting-Ting Wu, Ren Sun, Edward Usherwood, Jae U. Jung

Dartmouth Scholarship

Upon viral infection, cells undergo apoptosis as a defense against viral replication. Viruses, in turn, have evolved elaborate mechanisms to subvert apoptotic processes. Here, we report that a novel viral mitochondrial anti-apoptotic protein (vMAP) of murine gamma-herpesvirus 68 (gammaHV-68) interacts with Bcl-2 and voltage-dependent anion channel 1 (VDAC1) in a genetically separable manner. The N-terminal region of vMAP interacted with Bcl-2, and this interaction markedly increased not only Bcl-2 recruitment to mitochondria but also its avidity for BH3-only pro-apoptotic proteins, thereby suppressing Bax mitochondrial translocation and activation. In addition, the central and C-terminal hydrophobic regions of vMAP interacted with VDAC1. …

The Effects Of Human/Wildlife Conflict On The Potential For Community-Based Ecotourism In The Kasigau Region Of Southeast Kenya, Natalie Mountjoy

Masters Theses & Specialist Projects

Many believe community-based ecotourism (CBE) can assist in conservation efforts and community development; however, little research has been done to assess the potential of CBE in a specific region. As part of a large, long-term, international research project, I define three problematic areas that may impede successful CBE efforts in the Kasigau location of southeast Kenya: bushmeat utilization, community attitudes and wildlife abundance. Samples of meat purchased from butcheries and meat markets are identified to species using molecular analysis, community attitudes are ascertained via written social surveys and transect sampling methods are used to determine the relative abundance and diversity …

Auditory Hair Cell Regeneration And Gene Expression In Noise-Exposed Zebrafish (Danio Rerio), Julie Schuck

Masters Theses & Specialist Projects

Fishes are capable of regenerating sensory hair cells in the inner ear after exposure to excessive noise. However, a time course of auditory hair cell regeneration has not been characterized for zebrafish, nor has gene expression following noise exposure. To establish a time course of hair cell regeneration, adult zebrafish were exposed to a 100 Hz pure tone at 179 dB re 1 |u.Pa RMS for 36 hours, and then allowed to recover for 0 to 14 days before morphological analysis. Hair cell loss and recovery were determined using phalloidin and DAPI labeling to visualize hair cell bundles and nuclei, …

The Environmental Factors Regulating The Distribution Of Crayfish In The Upper Green River Basin Kentucky, Usa, Eva Ngulo

Masters Theses & Specialist Projects

Despite the importance of crayfish in aquatic systems there are major issues threatening their conservation, including invasive species, habitat alterations, and species with small distributions or have limited geographical ranges. There is limited information regarding native range, habitat requirements, life histories and biological interactions between crayfish species. In order to examine the relationship between lotic crayfish assemblages and environmental variables at both the watershed and reach scales, data were collected from 46 stream segments in the Upper Green River Basin of Kentucky, U.S.A. An independent sample t-test compared crayfish densities between segments with gravel - small cobble, and large cobble …

Sustainability Of Western Kentucky University: An Examination Of Campus Environmental Policies, Performance And Potential For Change, Christian Ryan-Downing

Masters Theses & Specialist Projects

Institutions of higher learning are in a pivotal position to address the environmental problems that global society faces now, but response to this challenge requires transformation in priorities and practices. Recognizing the impacts that universities have on the environment and the social and economic costs associated with these impacts, institutions of higher learning are changing policies and management to become more sustainable. Sustainability is defined by the World Commission on Environment and Development as "development that meets the needs of the present without compromising the ability of future generations to meet their own needs" (1987). To evaluate the environmental impacts …

Bactericidal Activity Of Extended 9-Glycyl-Amido-Minocyclines, Chang-Po Chen, Allen R. Zeiger, Dr. Eric Wickstrom

Department of Biochemistry and Molecular Biology Faculty Papers

The need for self-protecting polymer or alloy implants resistant to a broad spectrum of bacterial challenges led us to investigate covalent bonding of minocycline (MIN), a tetracycline derivative, to polystyrene beads and to titanium alloy foils by oligoethylene glycol spacers. 9-Hydrazino-acetyl-amido-MIN, and simpler glycylcycline derivatives, retained minimum inhibitory concentration (MIC) against Staphylococcus aureus comparable to MIN. However, PEG-glycyl-amido-MIN showed very low activity. Hence, we coupled 9-hydrazino-acetyl-amido-MIN to the aldehyde termini of oligoethylene glycol spacers bonded to polystyrene and titanium alloy surfaces to form acid-releasable hydrazone linkages. 9-Hydrazino-acetyl-amido-MIN was released from the monolayers more rapidly at pH 5.0 than at pH …

In Vitro Methods For Generating Highly Purified Ebv Associated Tumor Antigen-Specific T Cells By Using Solid Phase T Cell Selection System For Immunotherapy, Jongming Li, Bijoyesh Mookerjee, John Wagner, Neal Flomenberg

Department of Medical Oncology Faculty Papers

Adoptive cell transfer immunotherapy has been utilized to treat EBV related human malignancies including post-transplant lymphoproliferative diseases, Hodgkin's lymphoma and nasopharyngeal carcinoma. However, there are limited options available for tumor antigen-specific T cell purification. Here we describe a novel solid phase T cell selection system, in which monocytes or EBV transformed B-lymphocytes are immobilized on solid support for antigen-specific T cell purification. We hypothesize and prove that antigen-specific T cells recognize their cognate antigens and bind to them faster than non-antigen specific T cells. Therefore antigen-specific T cells can be concentrated on the surface after removing the non-adherent cells by …

A Dipeptidyl Aminopeptidase-Like Protein Remodels Gating Charge Dynamics In Kv4.2 Channels, Kevin Dougherty, Manuel Covarrubias

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Dipeptidyl aminopeptidase–like proteins (DPLPs) interact with Kv4 channels and thereby induce a profound remodeling of activation and inactivation gating. DPLPs are constitutive components of the neuronal Kv4 channel complex, and recent observations have suggested the critical functional role of the single transmembrane segment of these proteins (Zagha, E., A. Ozaita, S.Y. Chang, M.S. Nadal, U. Lin, M.J. Saganich, T. McCormack, K.O. Akinsanya, S.Y. Qi, and B. Rudy. 2005. J. Biol. Chem. 280:18853–18861). However, the underlying mechanism of action is unknown. We hypothesized that a unique interaction between the Kv4.2 channel and a DPLP found in brain (DPPX-S) may remodel the …

Adaptive Radiotherapy Planning On Decreasing Gross Tumor Volumes As Seen On Megavoltage Computed Tomography Images., Curtis Woodford, Slav Yartsev, R. Dar, Glenn Bauman, Jacob Van Dyk

Oncology Publications

PURPOSE: To evaluate gross tumor volume (GTV) changes for patients with non-small-cell lung cancer by using daily megavoltage (MV) computed tomography (CT) studies acquired before each treatment fraction on helical tomotherapy and to relate the potential benefit of adaptive image-guided radiotherapy to changes in GTV.

METHODS AND MATERIALS: Seventeen patients were prescribed 30 fractions of radiotherapy on helical tomotherapy for non-small-cell lung cancer at London Regional Cancer Program from Dec 2005 to March 2007. The GTV was contoured on the daily MVCT studies of each patient. Adapted plans were created using merged MVCT-kilovoltage CT image sets to investigate the advantages …

Leptospira Interrogans Endostatin-Like Outer Membrane Proteins Bind Host Fibronectin, Laminin And Regulators Of Complement, Brian Stevenson, Henry A. Choy, Marija Pinne, Matthew L. Rotondi, M. Clarke Miller, Edward Demoll, Peter Kraiczy, Anne E. Cooley, Trevor P. Creamer, Marc A. Suchard, Catherine A. Brissette, Ashutosh Verma, David A. Haake

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The pathogenic spirochete Leptospira interrogans disseminates throughout its hosts via the bloodstream, then invades and colonizes a variety of host tissues. Infectious leptospires are resistant to killing by their hosts' alternative pathway of complement-mediated killing, and interact with various host extracellular matrix (ECM) components. The LenA outer surface protein (formerly called LfhA and Lsa24) was previously shown to bind the host ECM component laminin and the complement regulators factor H and factor H-related protein-1. We now demonstrate that infectious L. interrogans contain five additional paralogs of lenA, which we designated lenB, lenC, lenD, lenE and lenF …

Anti-Tumor Effect Of Doxycycline On Glioblastoma Cells, Andrea Wang-Gillam, Eric Siegel, Debra A. Mayes, Laura F. Hutchins, Yi-Hong Zhou

Neuroscience, Cell Biology & Physiology Faculty Publications

AIM: Glioblastoma multiforme (GBM) is the most common primary brain tumor in humans, and it is highly invasive. Doxycycline, first identified as an antimicrobial agent, is a nonspecific inhibitor of matrix metalloproteinases (MMPs). Our objective was to investigate the anti-MMP effect of doxycycline at therapeutically acceptable levels on glioma cells in vitro.

METHODS: The MTT assay was used to determine the anti-proliferative effects of doxycycline. MMP2 activity and expression were determined by gelatinase zymography and real-time quantitative RT-PCR, respectively. Cell invasion was assessed by Matrigel invasion assay.

RESULTS: Doxycycline exerted mild anti-proliferative effects on all three glioma cell lines …

Perinatal Ph And Neuropsychological Outcomes At Age 3 Years In Children Born Preterm: An Exploratory Study, Kimberly A. Espy, Theresa E. Senn, David A. Charak, Jill Tyler, Sandra A. Wiebe

Developmental Cognitive Neuroscience Laboratory: Faculty and Staff Publications

The impact of extreme prematurity and related hypoxic-ischemic events on brain development recently has begun to be characterized with modern neuroimaging methods, although comparatively less is known about the neuropathology in those born at heavier birth weights. Even subclinical levels of perinatal hypoxia-ischemia, as indexed by perinatal blood pH, are related to intelligence in school-aged children born preterm. Given the impact of hypoxia-ischemia on white matter and the emerging evidence of specific executive and mathematic deficits in children born preterm, the impact of perinatal hypoxia-ischemia on these outcomes was explored in children at relatively low-risk for sequelae. In a sample …

A Bayesian Multilevel Modeling Approach For Data Query In Wireless Sensor Networks, H. Wang, H. Fang, K. A. Espy, D. Peng, H. Sharif

Developmental Cognitive Neuroscience Laboratory: Faculty and Staff Publications

In power-limited Wireless Sensor Network (WSN), it is important to reduce the communication load in order to achieve energy savings. This paper applies a novel statistic method to estimate the parameters based on the realtime data measured by local sensors. Instead of transmitting large real-time data, we proposed to transmit the small amount of dynamic parameters by exploiting both temporal and spatial correlation within and between sensor clusters. The temporal correlation is built on the level-1 Bayesian model at each sensor to predict local readings. Each local sensor transmits their local parameters learned from historical measurement data to their cluster …

Using Confirmatory Factor Analysis To Understand Executive Control In Preschool Children: I. Latent Structure, S. A. Wiebe, K. A. Espy, D. Charak

Developmental Cognitive Neuroscience Laboratory: Faculty and Staff Publications

Although many tasks have been developed recently to study executive control in the preschool years, the constructs that underlie performance on these tasks are poorly understood. In particular, it is unclear whether executive control is comprised of multiple, separable cognitive abilities (e.g., inhibition and working memory) or whether it is unitary in nature. A sample of 243 normally developing children between 2.25 and 6 years of age completed a battery of age appropriate executive control tasks. Confirmatory factor analysis (CFA) was used to compare multiple models of executive control empirically. A single-factor, general model was sufficient to account for the …

Augmented Hypothalamic Corticotrophin-Releasing Hormone Mrna And Corticosterone Responses To Stress In Adult Rats Exposed To Perinatal Hypoxia, Hershel Raff, Lauren Jacobson, William E. Cullinan

Biomedical Sciences Faculty Research and Publications

Stressful events before or just after parturition alter the subsequent phenotypical response to stress in a general process termed programming. Hypoxia during the period before and during parturition, and in the postnatal period, is one of the most common causes of perinatal distress, morbidity, and mortality. We have found that perinatal hypoxia (prenatal day 19 to postnatal day 14) augmented the corticosterone response to stress and increased basal corticotrophin-releasing hormone (CRH) mRNA levels in the parvocellular portion of the paraventricular nucleus (PVN) in 6-month-old rats. There was no effect on the levels of hypothalamic parvocellular PVN vasopressin mRNA, anterior pituitary …

Gene Family Encoding The Major Toxins Of Lethal Amanita Mushrooms, Heather E. Hallen-Adams, Hong Luo, John S. Scott-Craig, Jonathan D. Walton

Heather Hallen-Adams Publications

Amatoxins, the lethal constituents of poisonous mushrooms in the genus Amanita, are bicyclic octapeptides. Two genes in A. bisporigera, AMA1 and PHA1, directly encode α-amanitin, an amatoxin, and the related bicyclic heptapeptide phallacidin, a phallotoxin, indicating that these compounds are synthesized on ribosomes and not by nonribosomal peptide synthetases. α-Amanitin and phallacidin are synthesized as proproteins of 35 and 34 amino acids, respectively, from which they are predicted to be cleaved by a prolyl oligopeptidase. AMA1 and PHA1 are present in other toxic species of Amanita section Phalloidae but are absent from nontoxic species in other sections. …

Uniform Particles Of Pure And Silica Coated Cholesterol, Vuk Uskoković, Egon Matijević

Pharmacy Faculty Articles and Research

Uniform crystalline colloidal cholesterol particles of narrow size distribution were obtained by precipitation. The method consisted of adding a miscible non-solvent (water) into cholesterol solutions of different alcohols and acetone, without any additives. The properties of the resulting particles depended in a sensitive way on the concentration of all reactants, temperature, pH, ionic strength, and aging time. The major observed effects were due to the solubility of cholesterol, which was strongly affected by the solvent mixture and temperature. Precipitation in 1-propanol/water system yielded stable dispersions of well-defined particles, which were used to evaluate the effects of different experimental parameters on …

Relative Contributions Of Enterococcus Faecalis Og1rf Sortase-Encoding Genes, Srta And Bps (Srtc), To Biofilm Formation And A Murine Model Of Urinary Tract Infection, Kelvin D Kemp, Kavindra V Singh, Sreedhar R Nallapareddy, Barbara E Murray

Journal Articles

Deletion mutants of the two sortase genes of Enterococcus faecalis OG1RF were constructed. srtC (renamed here bps for biofilm and pilus-associated sortase) was previously shown to be necessary for the production of Ebp pili and important for biofilm formation and endocarditis. Here, we report that a srtA deletion mutant showed a small (5%) yet significant (P = 0.037) reduction in biofilm relative to OG1RF, while a DeltasrtA Deltabps double mutant showed a much greater reduction (74% versus OG1RF and 44% versus the Deltabps mutant). In a murine urinary tract infection (UTI), the 50% infective doses of both the DeltasrtA Deltabps …

The Role Of Sse1 In The De Novo Formation And Variant Determination Of The [Psi+] Prion, Qing Fan, Kyung-Won Park, Zhiqiang Du, Kevin A Morano, Liming Li

Journal Articles

Yeast prions are a group of non-Mendelian genetic elements transmitted as altered and self-propagating conformations. Extensive studies in the last decade have provided valuable information on the mechanisms responsible for yeast prion propagation. How yeast prions are formed de novo and what cellular factors are required for determining prion "strains" or variants--a single polypeptide capable of existing in multiple conformations to result in distinct heritable phenotypes--continue to defy our understanding. We report here that Sse1, the yeast ortholog of the mammalian heat-shock protein 110 (Hsp110) and a nucleotide exchange factor for Hsp70 proteins, plays an important role in regulating [PSI+] …

Increased Hemorrhagic Transformation And Altered Infarct Size And Localization After Experimental Stroke In A Rat Model Type 2 Diabetes, Adviye Ergul, Mostafa M. Elgebaly, Mary-Louise Risher, Weiguo Li, Hazem Elewa, Jeffrey A. Switzer, Christiana Hall, Anna Kozak, Susan C. Fagan

Biomedical Sciences

Background: Interruption of flow through of cerebral blood vessels results in acute ischemic stroke. Subsequent breakdown of the blood brain barrier increases cerebral injury by the development of vasogenic edema and secondary hemorrhage known as hemorrhagic transformation (HT). Diabetes is a risk factor for stroke as well as poor outcome of stroke. The current study tested the hypothesis that diabetes-induced changes in the cerebral vasculature increase the risk of HT and augment ischemic injury.

Methods: Diabetic Goto-Kakizaki (GK) or control rats underwent 3 hours of middle cerebral artery occlusion and 21 h reperfusion followed by evaluation of infarct size, hemorrhage …

Evaluating Forensic Dna Evidence - A Day-Long Workshop, Dan E. Krane, William C. Thompson

Biological Sciences Faculty Publications

No abstract provided.

Enhancement Of Efficacy Of Prrsv Vaccines By Altering The Glycosylation Pattern Of Viral Glycoproteins, Asit K. Pattnaik

School of Veterinary and Biomedical Sciences: Faculty Publications

PRRSV, the causative agent of PRRS is of major economic significance to the pork industry in the USA and around the world. Current commercial vaccine does not provide adequate protection against PRRSV outbreaks. Therefore, there is an urgent need for development of more efficacious vaccine to combat PRRS. Our previous studies have suggested that (i) induction of neutralizing antibody response is an important correlate of evaluating the efficacy of a vaccine; (ii) neutralizing antibodies can be enhanced by hypoglycosylation of the major surface glycoprotein (GP5). While it is known that GP5 plays a prominent role in neutralizing antibody induction, it …

Characterization Of Mazfsa, An Endoribonuclease From Staphylococcus Aureus, Zhibiao Fu, Niles P. Donegan, Guido Memmi, Ambrose L. Cheung

Dartmouth Scholarship

The mazEF homologs of Staphylococcus aureus, designated mazEF(sa), have been shown to cotranscribe with the sigB operon under stress conditions. In this study, we showed that MazEF(Sa), as with their Escherichia coli counterparts, compose a toxin-antitoxin module wherein MazF(Sa) leads to rapid cell growth arrest and loss in viable CFU upon overexpression. MazF(Sa) is a novel sequence-specific endoribonuclease which cleaves mRNA to inhibit protein synthesis. Using ctpA mRNA as the model substrate both in vitro and in vivo, we demonstrated that MazF(Sa) cleaves single-strand RNA preferentially at the 5' side of the first U or 3' side of the second …