Life Sciences Commons^™

Efficacy Of A T Cell-Biased Adenovirus Vector As A Zika Virus Vaccine, Brianna L. Bullard, Brigette N. Corder, Matthew J. Gorman, Michael S. Diamond, Eric A. Weaver

Nebraska Center for Virology: Faculty Publications

Zika virus (ZIKV) is a major public health concern due to the risk of congenital Zika syndrome in developing fetuses and Guillain-Barre syndrome in adults. Currently, there are no approved vaccines available to protect against infection. Adenoviruses are safe and highly immunogenic vaccine vectors capable of inducing lasting humoral and cellular immune responses. Here, we developed two Adenovirus (Ad) vectored Zika virus vaccines by inserting a ZIKV prM-E gene expression cassette into human Ad types 4 (Ad4-prM-E) and 5 (Ad5-prM-E). Immune correlates indicate that Ad5-prM-E vaccination induces both an anti-ZIKV antibody and T-cell responses whereas Ad4-prM-E vaccination only induces a …

Als Mutations Of Fus Suppress Protein Translation And Disrupt The Regulation Of Nonsense-Mediated Decay, Marisa Kamelgarn, Jing Chen, Lisha Kuang, Huan Jin, Edward J. Kasarskis, Haining Zhu

Toxicology and Cancer Biology Faculty Publications

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease characterized by preferential motor neuron death. Approximately 15% of ALS cases are familial, and mutations in the fused in sarcoma (FUS) gene contribute to a subset of familial ALS cases. FUS is a multifunctional protein participating in many RNA metabolism pathways. ALS-linked mutations cause a liquid–liquid phase separation of FUS protein in vitro, inducing the formation of cytoplasmic granules and inclusions. However, it remains elusive what other proteins are sequestered into the inclusions and how such a process leads to neuronal dysfunction and degeneration. In this study, we developed …

Manganese-Enhanced Magnetic Resonance Imaging: Overview And Central Nervous System Applications With A Focus On Neurodegeneration, Ryan A. Cloyd, Shon A. Koren, Jose F. Abisambra

Physiology Faculty Publications

Manganese-enhanced magnetic resonance imaging (MEMRI) rose to prominence in the 1990s as a sensitive approach to high contrast imaging. Following the discovery of manganese conductance through calcium-permeable channels, MEMRI applications expanded to include functional imaging in the central nervous system (CNS) and other body systems. MEMRI has since been employed in the investigation of physiology in many animal models and in humans. Here, we review historical perspectives that follow the evolution of applied MRI research into MEMRI with particular focus on its potential toxicity. Furthermore, we discuss the more current in vivo investigative uses of MEMRI in CNS investigations and …

Floxed-Cassette Allelic Exchange Mutagenesis Enables Markerless Gene Deletion In Chlamydia Trachomatis And Can Reverse Cassette-Induced Polar Effects, Gabrielle Keb, Robert Hayman, Kenneth A. Fields

Microbiology, Immunology, and Molecular Genetics Faculty Publications

As obligate intracellular bacteria, Chlamydia spp. have evolved numerous, likely intricate, mechanisms to create and maintain a privileged intracellular niche. Recent progress in elucidating and characterizing these processes has been bolstered by the development of techniques enabling basic genetic tractability. Florescence-reported allelic exchange mutagenesis (FRAEM) couples chromosomal gene deletion with the insertion of a selection cassette encoding antibiotic resistance and green fluorescent protein (GFP). Similar to other bacteria, many chlamydial genes exist within polycistronic operons, raising the possibility of polar effects mediated by insertion cassettes. Indeed, FRAEM-mediated deletion of Chlamydia trachomatis tmeA negatively impacts the expression of tmeB. We …

Dna Methylation By Restriction Modification Systems Affects The Global Transcriptome Profile In Borrelia Burgdorferi, Timothey Casselli, Yvonne Tourand, Adam Scheidegger, William K. Arnold, Anna Proulx, Brian Stevenson, Catherine A. Brissette

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Prokaryote restriction modification (RM) systems serve to protect bacteria from potentially detrimental foreign DNA. Recent evidence suggests that DNA methylation by the methyltransferase (MTase) components of RM systems can also have effects on transcriptome profiles. The type strain of the causative agent of Lyme disease, Borrelia burgdorferi B31, possesses two RM systems with N6-methyladenosine (m6A) MTase activity, which are encoded by the bbe02 gene located on linear plasmid lp25 and bbq67 on lp56. The specific recognition and/or methylation sequences had not been identified for either of these B. burgdorferi MTases, and it was not previously known whether these RM …

Lakeshore Modification Reduces Secondary Production Of Macroinvertebrates In Littoral But Not Deeper Zones, Marlene Pätzig, Yvonne Vadeboncoeur, Mario Brauns

Biological Sciences Faculty Publications

Littoral macroinvertebrates are an integral component of lake food webs, but their productivity may be affected by shoreline alteration. We hypothesized that human modification of lake shores simplifies habitat diversity, which, in turn, affects littoral macroinvertebrate production and patterns of depth–production relationships. Furthermore, we expected that lakeshore modification would favor nonnative species, potentially compensating for negative effects of lakeshore modification on production of native taxa. To test these ideas, we estimated benthic macroinvertebrate production in the upper littoral, middle littoral, and profundal zones of a large lowland lake (Lake Scharmützelsee) in Northeast Germany. We collected samples between April and November …

Mitochondrial Metabolism In Major Neurological Diseases, Zhengqiu Zhou, Grant L. Austin, Lyndsay E. A. Young, Lance A. Johnson, Ramon Sun

Molecular and Cellular Biochemistry Faculty Publications

Mitochondria are bilayer sub-cellular organelles that are an integral part of normal cellular physiology. They are responsible for producing the majority of a cell’s ATP, thus supplying energy for a variety of key cellular processes, especially in the brain. Although energy production is a key aspect of mitochondrial metabolism, its role extends far beyond energy production to cell signaling and epigenetic regulation–functions that contribute to cellular proliferation, differentiation, apoptosis, migration, and autophagy. Recent research on neurological disorders suggest a major metabolic component in disease pathophysiology, and mitochondria have been shown to be in the center of metabolic dysregulation and possibly …

H3k9 Methyltransferases And Demethylases Control Lung Tumor-Propagating Cells And Lung Cancer Progression, S. P. Rowbotham, F Li, A. F. M. Dost, S. M. Louie, B. P. Marsh, P. Pessina, C. R. Anbarasu, Christine Fillmore Brainson, S. J. Tuminello, A. Lieberman, S. Ryeom, T. M. Schlaeger, B. J. Aronow, H. Watanabe, K. K. Wong, C. F. Kim

Toxicology and Cancer Biology Faculty Publications

Epigenetic regulators are attractive anticancer targets, but the promise of therapeutic strategies inhibiting some of these factors has not been proven in vivo or taken into account tumor cell heterogeneity. Here we show that the histone methyltransferase G9a, reported to be a therapeutic target in many cancers, is a suppressor of aggressive lung tumor-propagating cells (TPCs). Inhibition of G9a drives lung adenocarcinoma cells towards the TPC phenotype by de-repressing genes which regulate the extracellular matrix. Depletion of G9a during tumorigenesis enriches tumors in TPCs and accelerates disease progression metastasis. Depleting histone demethylases represses G9a-regulated genes and TPC phenotypes. Demethylase inhibition …

Exploring The Neural Mechanisms Of Physics Learning, Jessica E. Bartley

FIU Electronic Theses and Dissertations

This dissertation presents a series of neuroimaging investigations and achievements that strive to deepen and broaden our understanding of human problem solving and physics learning. Neuroscience conceives of dynamic relationships between behavior, experience, and brain structure and function, but how neural changes enable human learning across classroom instruction remains an open question. At the same time, physics is a challenging area of study in which introductory students regularly struggle to achieve success across university instruction. Research and initiatives in neuroeducation promise a new understanding into the interactions between biology and education, including the neural mechanisms of learning and development. These …

Cell Specific Control Of The Pallidostriatal Pathway, Shubha Verma '19

Student Publications & Research

Parkinson’s Disease is a neurodegenerative disorder of the basal ganglia. The main cause for Parkinson’s Disease is the depletion of dopamine, a neurotransmitter. The basal ganglia contains four major nuclei: the substantia nigra, the subthalamic nucleus, the external globus pallidus, and the striatum. These nuclei communicate with each other by the use of neurons.

Stem Cell Generated Β-Cells: A Possible Solution To The Growing Problem Of Type 1 Diabetes, Danielle Rae Steffen

Biology: Student Scholarship & Creative Works

Type 1 diabetes is a growing problem throughout the world. At this time, there is no functional cure, only various treatment options. However, in recent years there has been a significant increase in both the quantity and quality of research into potential cures for type 1 diabetes. This has led to a variety of new possibilities, the most promising of which are β-cells generated from the patient’s own stem cells.

Isobavachalcone Sensitizes Cells To E2-Induced Paclitaxel Resistance By Down-Regulating Cd44 Expression In Er+ Breast Cancer Cells, Junfeng Shi, Yi Chen, Wenxing Chen, Cuiju Tang, Honghong Zhang, Yuetong Chen, Xiuwei H. Yang, Zhi Xu, Jingsun Wei, Jinfei Chen

Pharmacology and Nutritional Sciences Faculty Publications

Oestrogen receptor (ER) is expressed in approximately 60%‐70% of human breast cancer. Clinical trials and retrospective analyses have shown that ER‐positive (ER+) tumours are more tolerant to chemotherapeutic drug resistance than ER‐negative (ER−) tumours. In addition, isobavachalcone (IBC) is known as a kind of phytoestrogen with antitumour effect. However, the underlying mechanism of IBC in ER+ breast cancer needs to be elucidated further. Our in vitro experiments showed that IBC could attenuate 17β‐estradiol (E₂)‐induced paclitaxel resistance and that E₂ could stimulate CD44 expression in ER+ breast cancer cells but not in ER− cells. Meanwhile, E₂ could …

Proteomics Of Human Liver Membrane Transporters: A Focus On Fetuses And Newborn Infants., Bianca D. Van Groen, Evita Van De Steeg, Miriam G. Mooij, Marola M H Van Lipzig, Barbara A E De Koning, Robert M. Verdijk, Heleen M. Wortelboer, R Gaedigk, Chengpeng Bi, J Steven Leeder, Ron H N Van Schaik, Joost Van Rosmalen, Dick Tibboel, Wouter H. Vaes, Saskia N. De Wildt

Manuscripts, Articles, Book Chapters and Other Papers

BACKGROUND: Hepatic membrane transporters are involved in the transport of many endogenous and exogenous compounds, including drugs. We aimed to study the relation of age with absolute transporter protein expression in a cohort of 62 mainly fetus and newborn samples.

METHODS: Protein expressions of BCRP, BSEP, GLUT1, MCT1, MDR1, MRP1, MRP2, MRP3, NTCP, OCT1, OATP1B1, OATP1B3, OATP2B1 and ATP1A1 were quantified with LC-MS/MS in isolated crude membrane fractions of snap-frozen post-mortem fetal and pediatric, and surgical adult liver samples. mRNA expression was quantified using RNA sequencing, and genetic variants with TaqMan assays. We explored relationships between protein expression and age …

Hyperhomocysteinemia As A Risk Factor For Vascular Contributions To Cognitive Impairment And Dementia, Brittani R. Price, Donna M. Wilcock, Erica M. Weekman

Physiology Faculty Publications

Behind only Alzheimer’s disease, vascular contributions to cognitive impairment and dementia (VCID) is the second most common cause of dementia, affecting roughly 10–40% of dementia patients. While there is no cure for VCID, several risk factors for VCID, such as diabetes, hypertension, and stroke, have been identified. Elevated plasma levels of homocysteine, termed hyperhomocysteinemia (HHcy), are a major, yet underrecognized, risk factor for VCID. B vitamin deficiency, which is the most common cause of HHcy, is common in the elderly. With B vitamin supplementation being a relatively safe and inexpensive therapeutic, the treatment of HHcy-induced VCID would seem straightforward; however, …

Heat Shock Protein 40 And Immune Function In Altered Gravity, Amber M. Paul, Brooke D. Shepard, Sharmila Bhattacharya

Publications

In space, astronauts are more susceptible to pathogens, viral reactivation and immunosuppression, which poses limits to their health and the mission. Interestingly, during space flight, stress-inducible heat shock proteins (HSP) are robustly induced, and the overexpression of HSPs have been implicated in immune dysregulation, therefore HSPs may be critically involved in regulating immune homeostasis. HSP40/DNAJ1 plays a major role in proper protein translation and folding. Its loss of function has been implicated in susceptibility to microbial infection, while its overexpression has been implicated in autoimmunity, collectively suggesting its complicated, but necessary, role in maintaining immunological function. To determine the role …

Neutrophil To Lymphocyte Ratio: A Prognostic Indicator For Astronaut Health, Amber M. Paul, Siddhita D. Mhatre, Egle Cekanaviciute, Ann-Sofie Schreurs, Candice G.T. Tahimic, Ruth K. Globus, Brian Crucian, Sharmila Bhattacharya

Publications

Short-term and long-term spaceflight missions can cause immune system dysfunction in astronauts. Recent studies indicate elevated white blood cells (WBC) and polymorphonuclear neutrophils (PMN) in astronaut blood, along with unchanged or reduced lymphocyte counts, and reduced T cell function, during short-(days) and long-(months) term spaceflight. A high PMN to lymphocyte ratio (NLR) can acts as a strong predictor of poor prognosis in cancer, and as a biomarker for subclinical inflammation in humans and chronic stress in mouse models, however, the NLR has not yet been identified as a predictor of astronaut health during spaceflight. For this, complete blood cell count …

Kaposi’S Sarcoma-Associated Herpesvirus Seropositivity Is Associated With Type 2 Diabetes Mellitus: A Case–Control Study In Xinjiang, China, Meng Cui, Qiwen Fang, Jun Zheng, Zhanjun Shu, Yin Chen, Yage Fan, Juan Zhao, Charles Wood, Tiejun Zhang, Yan Zeng

Nebraska Center for Virology: Faculty Publications

Objective: To assess the potential relationship between Kaposi’s sarcoma-associated herpesvirus (KSHV) infection and type 2 diabetes mellitus (DM-2) in Xinjiang, China.

Methods: A case–control study of consecutively included DM-2 patients and normal controls was conducted among the Uygur and Han populations in Xinjiang Uygur Autonomous Region, China. Blood samples were collected and KSHV seroprevalence, antibody titers, and viral load were investigated. Logistic regression analysis and multiple linear regression analysis were applied to explore determinants of the main outcome measures.

Results: A total of 324 patients with DM-2 and 376 normal controls were included. The seroprevalence of KSHV was 49.1% (95% …

Alpha-Amino-Beta-Carboxy-Muconate-Semialdehyde Decarboxylase Controls Dietary Niacin Requirements For Nad+ Synthesis, Laura Palzer, Jessica J. Bader, Frances Angel, Megan Witzel, Sydney Blaser, Alexis Mcneil, Miles K. Wandersee, N. Adrian Leu, Christopher J. Lengner, Clara E. Cho, Kevin D. Welch, James B. Kirkland, Ralph G. Meyer, Mirella L. Meyer-Ficca

Animal, Dairy, and Veterinary Science Faculty Publications

NAD⁺ is essential for redox reactions in energy metabolism and necessary for DNA repair and epigenetic modification. Humans require sufficient amounts of dietary niacin (nicotinic acid, nicotinamide, and nicotinamide riboside) for adequate NAD⁺ synthesis. In contrast, mice easily generate sufficient NAD⁺ solely from tryptophan through the kynurenine pathway. We show that transgenic mice with inducible expression of human alpha-amino-beta-carboxy-muconate-semialdehyde decarboxylase (ACMSD) become niacin dependent similar to humans when ACMSD expression is high. On niacin-free diets, these acquired niacin dependency (ANDY) mice developed reversible, mild-to-severe NAD⁺ deficiency, depending on the nutrient composition of the diet. NAD deficiency …

Stress-Induced Heat Shock Protein 40 And Immune Function In Altered Gravity, Amber M. Paul, Brooke D. Shepard, Sharmila Bhattacharya

Publications

In space, astronauts are more susceptible to pathogens, viral reactivation and immunosuppression, which poses limits to their health and the mission. Interestingly, during space flight, stress-inducible heat shock proteins (HSP) are robustly induced, and the overexpression of HSPs have been implicated in immune dysregulation, therefore HSPs may be critically involved in regulating immune homeostasis. HSP40/DNAJ1 plays a major role in proper protein translation and folding. Its loss of function has been implicated in susceptibility to microbial infection, while its overexpression has been implicated in autoimmunity, collectively suggesting its complicated, but necessary, role in maintaining immunological function. To determine the role …

Gene Gangs Of The Chloroviruses: Conserved Clusters Of Collinear Monocistronic Genes, Phillip Seitzer, Adrien Jeanniard, Fangrui Ma, James L. Van Etten, Marc T. Facciotti, David D. Dunigan

Nebraska Center for Virology: Faculty Publications

Chloroviruses (family Phycodnaviridae) are dsDNA viruses found throughout the world’s inland waters. The open reading frames in the genomes of 41 sequenced chloroviruses (330 + 40 kbp each) representing three virus types were analyzed for evidence of evolutionarily conserved local genomic “contexts”, the organization of biological information into units of a scale larger than a gene. Despite a general loss of synteny between virus types, we informatically detected a highly conserved genomic context defined by groups of three or more genes that we have termed “gene gangs”. Unlike previously described local genomic contexts, the definition of gene gangs requires only …

Antibody Epitope Specificity For Dsdna Phosphate Backbone Is An Intrinsic Property Of The Heavy Chain Variable Germline Gene Segment Used, Tatjana Srdic-Rajic, Heinz Kohler, Vladimir Jurisic, Radmila Metlas

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Analysis of protein sequences by the informational spectrum method (ISM) enables characterization of their specificity according to encoded information represented with defined frequency (F). Our previous data showed that F(0.367) is characteristic for variable heavy chain (VH) domains (a combination of variable (V), diversity (D) and joining (J) gene segments) of the anti-phosphocholine (PC) T15 antibodies and mostly dependent on the CDR2 region, a site for PC phosphate group binding. Because the T15 dsDNA-reactive U4 mutant also encodes F(0.367), we hypothesized that the same frequency may also be characteristic for anti-DNA antibodies. Data obtained from an analysis of 60 spontaneously …

Vancomycin Delays Clindamycin-Induced Fatality In The Hamster Model Of Clostridioides [Clostridium] Difficile Infection, Amelia E. Fox-King, Chrisabelle Mefferd, Jacqueline R. Phan, Nancy O. Nou, Ernesto Abel-Santos, Brian P. Hedlund

LSAMP Poster Presentations

Antibiotics can leave the host gut microbiome susceptible to Clostridioides [Clostridium] difficile colonization and lethal toxin production. For instance, clindamycin-induced susceptibility to C. difficile infection (CDI) results in rapid fatality in hamster models, yet vancomycin has been shown to offer increased survival in hamsters challenged with C. difficile. We aim to develop an antibiotic treatment that will facilitate CDI susceptibility without prompt fatality in hamster models. An antibiotic regimen starting with a continuous vancomycin treatment along with a single clindamycin dosage is thought to reduce the major disruption in the indigenous gut microbiome and prevent clindamycin-induced death. …

Identification Of Chst9 As A Candidate Gene For Schizophrenia From Whole Genome Sequencing, Christopher Sharp, Jingchun Chen, Marvi Moreno, Mahtab Hamid, Francisco Servin, Bita Bashy, Travis Mize

LSAMP Poster Presentations

Recent results imply that rare variants contribute to the risk of schizophrenia. We conducted whole genome sequencing for 99 subjects from 20 Chinese families (parents and at least two siblings with a schizophrenia diagnosis and one unaffected sibling). Of the 9 frameshift mutations identified in more than 2 families, one was at chromosome 10:125780762 on the Carbohydrate Sulfotransferase 15 (CHST15) gene and another at chromosome 18:24722723 on the Carbohydrate Sulfotransferase 9 (CHST9) gene. We observed these deletions in 4 affected persons of two families from whole. At least two types of mutations (one or three bases insertion) have been identified …

The Learning Loss Effect In Genetics: What Ideas Do Students Retain Or Lose After Instruction?, Amber Todd, William L. Romine

Biological Sciences Faculty Publications

Modern genetics is a relatively new domain, but it is increasingly important for students to have a firm grasp on the content, because genetic technologies are becoming more commonplace. In a previous study, we used the Learning Progression-based Assessment of Modern Genetics to assess high school students’ knowledge of genetics concepts after an intensive inquiry-based genetics instructional period. Given that this type of intensive inquiry-based instruction is unique, we are now investigating how students’ knowledge of genetics changes after instruction (i.e., learning loss effect). Using a six-measure longitudinal design, we found that students retained significant gains in five of the …

Cysteine Residues Contribute To The Dimerization And Enzymatic Activity Of Human Nuclear Dutp Nucleotidohydrolase (Ndut)., Shawna M Rotoli, Julia L Jones, Salvatore J Caradonna

Rowan-Virtua School of Osteopathic Medicine Departmental Research

dUTPase is an enzyme found in all organisms that have thymine as a constituent of DNA. Through evolution, humans have two major isoforms of dUTPase: a mitochondrial (mDut) and a nuclear (nDut) isoform. The nuclear isoform of dUTPase is a 164-amino-acids-long protein containing three cysteine residues. nDut's starting methionine is post-translationally cleaved, leaving four unique amino acids on its amino-terminus including one cysteine residue (C3). These are not present in the mitochondrial isoform (mDut). Using mass spectrometry analyses of recombinant dUTPase constructs, we have discovered an intermolecular disulfide bridge between cysteine-3 of each nDut monomer. We have found that these …

Editorial: Ion Channel Trafficking And Cardiac Arrhythmias, Marcel A. G. Van Der Heyden, Brian P. Delisle, Hugues Abriel

Physiology Faculty Publications

No abstract provided.

Effect Of The Synthetic Bile Salt Analog Camsa On The Hamster Model Of Clostridium Difficile Infection, Amber Howerton, Cale O. Seymour, Senthil K. Murugapiran, Zhenlin Liao, Jacqueline R. Phan, Alan Estrada, Adam J. Wagner, Chrisabelle C. Mefferd, Brian P. Hedlund, Ernesto Abel-Santos

Life Sciences Faculty Research

Clostridium difficile infection (CDI) is the leading cause of antibiotic-associated diarrhea and has gained worldwide notoriety due to emerging hypervirulent strains and the high incidence of recurrence. We previously reported protection of mice from CDI using the antigerminant bile salt analog CamSA. Here we describe the effects of CamSA in the hamster model of CDI. CamSA treatment of hamsters showed no toxicity and did not affect the richness or diversity of gut microbiota; however, minor changes in community composition were observed. Treatment of C. difficile-challenged hamsters with CamSA doubled the mean time to death, compared to control hamsters. However, CamSA …

Astrocyte Activation And The Calcineurin/Nfat Pathway In Cerebrovascular Disease, Susan D. Kraner, Christopher M. Norris

Sanders-Brown Center on Aging Faculty Publications

Calcineurin (CN) is a Ca²⁺/calmodulin-dependent protein phosphatase with high abundance in nervous tissue. Though enriched in neurons, CN can become strongly induced in subsets of activated astrocytes under different pathological conditions where it interacts extensively with the nuclear factor of activated T cells (NFATs). Recent work has shown that regions of small vessel damage are associated with the upregulation of a proteolized, highly active form of CN in nearby astrocytes, suggesting a link between the CN/NFAT pathway and chronic cerebrovascular disease. In this Mini Review article, we discuss CN/NFAT signaling properties in the context of vascular disease and …

Experimental Evaluation Of The Importance Of Colonization History In Early-Life Gut Microbiota Assembly, Inés Martínez, Maria X. Maldonado-Gomez, João Carlos Gomes-Neto, Hatem Kittana, Hua Ding, Robert J. Schmaltz, Payal Joglekar, Roberto Jiménez Cardona, Nathan L Marsteller, Steven W. Kembel, Andrew K. Benson, Daniel A. Peterson, Amanda Ramer-Tait, Jens C. Walter

Department of Food Science and Technology: Faculty Publications

The factors that govern assembly of the gut microbiota are insufficiently understood. Here, we test the hypothesis that inter-individual microbiota variation can arise solely from differences in the order and timing by which the gut is colonized early in life. Experiments in which mice were inoculated in sequence either with two complex seed communities or a cocktail of four bacterial strains and a seed community revealed that colonization order influenced both the outcome of community assembly and the ecological success of individual colonizers. Historical contingency and priority effects also occurred in Rag1^-/- mice, suggesting that the adaptive immune system …

Iron-Dependent Cleavage Of Ribosomal Rna During Oxidative Stress In The Yeast Saccharomyces Cerevisiae, Jessica A Zinskie, Arnab Ghosh, Brandon M Trainor, Daniel Shedlovskiy, Dimitri G Pestov, Natalia Shcherbik

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Stress-induced strand breaks in rRNA have been observed in many organisms, but the mechanisms by which they originate are not well-understood. Here we show that a chemical rather than an enzymatic mechanism initiates rRNA cleavages during oxidative stress in yeast (Saccharomyces cerevisiae). We used cells lacking the mitochondrial glutaredoxin Grx5 to demonstrate that oxidant-induced cleavage formation in 25S rRNA correlates with intracellular iron levels. Sequestering free iron by chemical or genetic means decreased the extent of rRNA degradation and relieved the hypersensitivity of grx5Δ cells to the oxidants. Importantly, subjecting purified ribosomes to an in vitro iron/ascorbate …