Internal Medicine Commons^™

Hur Controls Glutaminase Rna Metabolism, Douglas Adamoski, Larissa M Dos Reis, Ana Carolina Paschoalini Mafra, Felipe Corrêa-Da-Silva, Pedro Manoel Mendes De Moraes-Vieira, Ioana Berindan-Neagoe, George A Calin, Sandra Martha Gomes Dias

Student and Faculty Publications

Glutaminase (GLS) is directly related to cell growth and tumor progression, making it a target for cancer treatment. The RNA-binding protein HuR (encoded by the ELAVL1 gene) influences mRNA stability and alternative splicing. Overexpression of ELAVL1 is common in several cancers, including breast cancer. Here we show that HuR regulates GLS mRNA alternative splicing and isoform translation/stability in breast cancer. Elevated ELAVL1 expression correlates with high levels of the glutaminase isoforms C (GAC) and kidney-type (KGA), which are associated with poor patient prognosis. Knocking down ELAVL1 reduces KGA and increases GAC levels, enhances glutamine anaplerosis into the TCA cycle, and …

Hammerhead-Type Fxr Agonists Induce An Enhancer Rna Fincor That Ameliorates Nonalcoholic Steatohepatitis In Mice, Jinjing Chen, Ruoyu Wang, Feng Xiong, Hao Sun, Byron Kemper, Wenbo Li, Jongsook Kemper

Faculty and Staff Publications

The nuclear receptor, farnesoid X receptor (FXR/NR1H4), is increasingly recognized as a promising drug target for metabolic diseases, including nonalcoholic steatohepatitis (NASH). Protein-coding genes regulated by FXR are well known, but whether FXR also acts through regulation of long non-coding RNAs (lncRNAs), which vastly outnumber protein-coding genes, remains unknown. Utilizing RNA-seq and global run-on sequencing (GRO-seq) analyses in mouse liver, we found that FXR activation affects the expression of many RNA transcripts from chromatin regions bearing enhancer features. Among these we discovered a previously unannotated liver-enriched enhancer-derived lncRNA (eRNA), termed FXR-induced non-coding RNA (

N6-Methyladenosine-Mediated Overexpression Of Long Noncoding Rna Adamts9-As2 Triggers Neuroblastoma Differentiation Via Regulating Lin28b/Let-7/Mycn Signaling, Yun Liu, Jun Zhang, Fang Cao, Xiaobao Dong, Jie Li, Yanna Cao, Zhanglin Li, Yan Guo, Jie Yan, Yuanyuan Liu, Qiang Zhao

Student and Faculty Publications

Neuroblastomas have shed light on the differentiation disorder that is associated with spontaneous regression or differentiation in the same tumor at the same time. Long noncoding RNAs (lncRNAs) actively participate in a broad spectrum of biological processes. However, the detailed molecular mechanisms underlying lncRNA regulation of differentiation in neuroblastomas remain largely unknown. Here, we sequenced clinical samples of ganglioneuroma, ganglioneuroblastoma, and neuroblastoma. We compared transcription profiles of neuroblastoma cells, ganglion cells, and intermediate state cells; verified the profiles in a retinoic acid-induced cell differentiation model and clinical samples; and screened out the lncRNA ADAMTS9 antisense RNA 2 (ADAMTS9-AS2), which contributed …

Liposome-Based Carriers For Crispr Genome Editing, Xing Yin, Romain Harmancey, David D Mcpherson, Hyunggun Kim, Shao-Ling Huang

Faculty and Staff Publications

The CRISPR-based genome editing technology, known as clustered regularly interspaced short palindromic repeats (CRISPR), has sparked renewed interest in gene therapy. This interest is accompanied by the development of single-guide RNAs (sgRNAs), which enable the introduction of desired genetic modifications at the targeted site when used alongside the CRISPR components. However, the efficient delivery of CRISPR/Cas remains a challenge. Successful gene editing relies on the development of a delivery strategy that can effectively deliver the CRISPR cargo to the target site. To overcome this obstacle, researchers have extensively explored non-viral, viral, and physical methods for targeted delivery of CRISPR/Cas9 and …

Molecular Mechanisms Of Snorna-Il-15 Crosstalk In Adipocyte Lipolysis And Nk Cell Rejuvenation, Yaohua Zhang, Zilong Zhao, Lisa A Huang, Yuan Liu, Jun Yao, Chengcao Sun, Yajuan Li, Zhao Zhang, Youqiong Ye, Fei Yuan, Tina K Nguyen, Nikhil Reddy Garlapati, Andrew Wu, Sergey D Egranov, Abigail S Caudle, Aysegul A Sahin, Bora Lim, Laura Beretta, George A Calin, Dihua Yu, Mien-Chie Hung, Michael A Curran, Katayoun Rezvani, Boyi Gan, Zhi Tan, Leng Han, Chunru Lin, Liuqing Yang

Student and Faculty Publications

Obesity, in which the functional importance of small nucleolar RNAs (snoRNAs) remains elusive, correlates with risk for many cancer types. Here, we identify that the serum copies of adipocyte-expressed SNORD46 correlate with body mass index (BMI), and serum SNORD46 antagonizes interleukin-15 (IL-15) signaling. Mechanically, SNORD46 binds IL-15 via G11, and G11A (a mutation that significantly enhances binding affinity) knockin drives obesity in mice. Functionally, SNORD46 blocks IL-15-induced, FER kinase-dependent phosphorylation of platelet glycoprotein 4 (CD36) and monoglyceride lipase (MGLL) in adipocytes, leading to inhibited lipolysis and browning. In natural killer (NK) cells, SNORD46 suppresses the IL-15-dependent autophagy, leading to reduced …

Comparative Analyses Define Differences Between Bhd-Associated Renal Tumour And Sporadic Chromophobe Renal Cell Carcinoma, Ryosuke Jikuya, Todd A Johnson, Kazuhiro Maejima, Jisong An, Young-Seok Ju, Hwajin Lee, Kyungsik Ha, Woojeung Song, Youngwook Kim, Yuki Okawa, Shota Sasagawa, Yuki Kanazashi, Masashi Fujita, Seiya Imoto, Taku Mitome, Shinji Ohtake, Go Noguchi, Sachi Kawaura, Yasuhiro Iribe, Kota Aomori, Tomoyuki Tatenuma, Mitsuru Komeya, Hiroki Ito, Yusuke Ito, Kentaro Muraoka, Mitsuko Furuya, Ikuma Kato, Satoshi Fujii, Haruka Hamanoue, Tomohiko Tamura, Masaya Baba, Toshio Suda, Tatsuhiko Kodama, Kazuhide Makiyama, Masahiro Yao, Brian M Shuch, Christopher J Ricketts, Laura S Schmidt, W Marston Linehan, Hidewaki Nakagawa, Hisashi Hasumi

Student and Faculty Publications

BACKGROUND: Birt-Hogg-Dubé (BHD) syndrome, caused by germline alteration of folliculin (FLCN) gene, develops hybrid oncocytic/chromophobe tumour (HOCT) and chromophobe renal cell carcinoma (ChRCC), whereas sporadic ChRCC does not harbor FLCN alteration. To date, molecular characteristics of these similar histological types of tumours have been incompletely elucidated.

METHODS: To elucidate renal tumourigenesis of BHD-associated renal tumours and sporadic renal tumours, we conducted whole genome sequencing (WGS) and RNA-sequencing (RNA-seq) of sixteen BHD-associated renal tumours from nine unrelated BHD patients, twenty-one sporadic ChRCCs and seven sporadic oncocytomas. We then compared somatic mutation profiles with FLCN variants and RNA expression profiles between BHD-associated …

Protective Role Of Colitis In Inflammatory Arthritis Via Propionate-Producing Bacteroides In The Gut, Hoh-Jeong Shon, Yu-Mi Kim, Kyeong Seog Kim, Jin-Ouk Choi, Sang-Hyun Cho, Sujin An, Se-Hyeon Park, Yong-Joon Cho, Joo-Hong Park, Sang-Uk Seo, Joo-Youn Cho, Wan-Uk Kim, Donghyun Kim

Student and Faculty Publications

OBJECTIVES: To investigate whether and how inflammatory disease in the intestine influences the development of arthritis, considering that organ-to-organ communication is associated with many physiological and pathological events.

METHODS: First, mice were given drinking water containing dextran sodium sulfate (DSS) and then subjected to inflammatory arthritis. We compared the phenotypic symptoms between the cohoused and separately-housed mice. Next, donor mice were divided into DSS-treated and untreated groups and then cohoused with recipient mice. Arthritis was then induced in the recipients. The fecal microbiome was analyzed by 16S rRNA amplicon sequencing. We obtained type strains of the candidate bacteria and generated …

A Comparative Study Of Cellular Diversity Between The Xenopus Pronephric And Mouse Metanephric Nephron, Mark E Corkins, Maryanne Achieng, Bridget D Delay, Vanja Krneta-Stankic, Margo P Cain, Brandy L Walker, Jichao Chen, Nils O Lindström, Rachel K Miller

Student and Faculty Publications

The kidney is an essential organ that ensures bodily fluid homeostasis and removes soluble waste products from the organism. Nephrons, the functional units of the kidney, comprise a blood filter, the glomerulus or glomus, and an epithelial tubule that processes the filtrate from the blood or coelom and selectively reabsorbs solutes, such as sugars, proteins, ions, and water, leaving waste products to be eliminated in the urine. Genes coding for transporters are segmentally expressed, enabling the nephron to sequentially process the filtrate. The Xenopus embryonic kidney, the pronephros, which consists of a single large nephron, has served as a valuable …

Association Of Mrna Vaccination With Clinical And Virologic Features Of Covid-19 Among Us Essential And Frontline Workers, The Heroes-Recover Network, Mark G Thompson, Sarang K Yoon, Allison L Naleway, Jennifer Meece, Thomas P Fabrizio, Alberto J Caban-Martinez, Jefferey L Burgess, Manjusha Gaglani, Lauren E W Olsho, Allen Bateman, Jessica Lundgren, Lauren Grant, Andrew L Phillips, Holly C Groom, Elisha Stefanski, Natasha Schaefer Solle, Katherine Ellingson, Karen Lutrick, Kayan Dunnigan, Meredith G Wesley, Kyley Guenther, Angela Hunt, Josephine Mak, Kurt T Hegmann, Jennifer L Kuntz, Adam Bissonnette, James Hollister, Spencer Rose, Tyler C Morrill, Karley Respet, Ashley L Fowlkes, Matthew S Thiese, Patrick Rivers, Meghan K Herring, Marilyn J Odean, Young M Yoo, Matthew Brunner, Edward J Bedrick, Deanna E Fleary, John T Jones, Jenna Praggastis, James Romine, Monica Dickerson, Sana M Khan, Julie Mayo Lamberte, Shawn Beitel, Richard J Webby, Harmony L Tyner

Student and Faculty Publications

IMPORTANCE: Data on the epidemiology of mild to moderately severe COVID-19 are needed to inform public health guidance.

OBJECTIVE: To evaluate associations between 2 or 3 doses of mRNA COVID-19 vaccine and attenuation of symptoms and viral RNA load across SARS-CoV-2 viral lineages.

DESIGN, SETTING, AND PARTICIPANTS: A prospective cohort study of essential and frontline workers in Arizona, Florida, Minnesota, Oregon, Texas, and Utah with COVID-19 infection confirmed by reverse transcriptase-polymerase chain reaction testing and lineage classified by whole genome sequencing of specimens self-collected weekly and at COVID-19 illness symptom onset. This analysis was conducted among 1199 participants with SARS-CoV-2 …

Patient-Derived Ipscs Link Elevated Mitochondrial Respiratory Complex I Function To Osteosarcoma In Rothmund-Thomson Syndrome, Brittany E Jewell, An Xu, Dandan Zhu, Mo-Fan Huang, Linchao Lu, Mo Liu, Erica L Underwood, Jun Hyoung Park, Huihui Fan, Julian A Gingold, Ruoji Zhou, Jian Tu, Zijun Huo, Ying Liu, Weidong Jin, Yi-Hung Chen, Yitian Xu, Shu-Hsia Chen, Nino Rainusso, Nathaniel K Berg, Danielle A Bazer, Christopher Vellano, Philip Jones, Holger K Eltzschig, Zhongming Zhao, Benny Abraham Kaipparettu, Ruiying Zhao, Lisa L Wang, Dung-Fang Lee

Faculty and Staff Publications

Rothmund-Thomson syndrome (RTS) is an autosomal recessive genetic disorder characterized by poikiloderma, small stature, skeletal anomalies, sparse brows/lashes, cataracts, and predisposition to cancer. Type 2 RTS patients with biallelic RECQL4 pathogenic variants have multiple skeletal anomalies and a significantly increased incidence of osteosarcoma. Here, we generated RTS patient-derived induced pluripotent stem cells (iPSCs) to dissect the pathological signaling leading to RTS patient-associated osteosarcoma. RTS iPSC-derived osteoblasts showed defective osteogenic differentiation and gain of in vitro tumorigenic ability. Transcriptome analysis of RTS osteoblasts validated decreased bone morphogenesis while revealing aberrantly upregulated mitochondrial respiratory complex I gene expression. RTS osteoblast metabolic assays …

Impact Of Diabetes On The Gut And Salivary Iga Microbiomes, Eric L Brown, Heather T Essigmann, Kristi L Hoffman, Noah W Palm, Sarah M Gunter, Joel M Sederstrom, Joseph F Petrosino, Goo Jun, David Aguilar, William B Perkison, Craig L Hanis, Herbert L Dupont

Student and Faculty Publications

Mucosal surfaces like those present in the lung, gut, and mouth interface with distinct external environments. These mucosal gateways are not only portals of entry for potential pathogens but also homes to microbial communities that impact host health. Secretory immunoglobulin A (SIgA) is the single most abundant acquired immune component secreted onto mucosal surfaces and, via the process of immune exclusion, shapes the architecture of these microbiomes. Not all microorganisms at mucosal surfaces are targeted by SIgA; therefore, a better understanding of the SIgA-coated fraction may identify the microbial constituents that stimulate host immune responses in the context of health …

Long Noncoding Rna H19x Is A Key Mediator Of Tgf-Β-Driven Fibrosi, Elena Pachera, Shervin Assassi, Gloria A Salazar, Mara Stellato, Florian Renoux, Adam Wunderlin, Przemyslaw Blyszczuk, Robert Lafyatis, Fina Kurreeman, Jeska De Vries-Bouwstra, Tobias Messemaker, Carol A Feghali-Bostwick, Gerhard Rogler, Wouter T Van Haaften, Gerard Dijkstra, Fiona Oakley, Maurizio Calcagni, Janine Schniering, Britta Maurer, Jörg Hw Distler, Gabriela Kania, Mojca Frank-Bertoncelj, Oliver Distler

Faculty and Staff Publications

TGF-β is a master regulator of fibrosis, driving the differentiation of fibroblasts into apoptosis-resistant myofibroblasts and sustaining the production of extracellular matrix (ECM) components. Here, we identified the nuclear long noncoding RNA (lncRNA) H19X as a master regulator of TGF-β-driven tissue fibrosis. H19X was consistently upregulated in a wide variety of human fibrotic tissues and diseases and was strongly induced by TGF-β, particularly in fibroblasts and fibroblast-related cells. Functional experiments following H19X silencing revealed that H19X was an obligatory factor for TGF-β-induced ECM synthesis as well as differentiation and survival of ECM-producing myofibroblasts. We showed that H19X regulates DDIT4L gene …

The Non-Coding Rnome After Splenectomy, Mihnea P Dragomir, Stefan Tudor, Keishi Okubo, Masayoshi Shimizu, Meng Chen, Dana Elena Giza, William Ruixian He, Cristina Ivan, George A Calin, Catalin Vasilescu

Faculty and Staff Publications

Splenectomy is a common surgical procedure performed in millions of people worldwide. Epidemiologic data show that splenectomy is followed by infectious (sepsis) and non-infectious complications, with unknown mechanisms. In order to explore the role of the non-coding transcripts involved in these complications, we analysed a panel of circulating microRNAs (miRNAs), which were previously reported to be deregulated in sepsis, in the plasma of splenectomized patients. MiR-223 was overexpressed immediately and late after splenectomy, while miR-146a was overexpressed immediately after splenectomy, returning latter to basal levels; and miR-16, miR-93, miR-26a and miR-26b were overexpressed only late after splenectomy, suggesting similarities with …

Human Dna Exonuclease Trex1 Is Also An Exoribonuclease That Acts On Single-Stranded Rna, Fenghua Yuan, Tanmay Dutta, Ling Wang, Lei Song, Liya Gu, Liangyue Qian, Anaid Benitez, Shunbin Ning, Arun Malhotra, Murray P. Deutcher, Yanbin Zhang

ETSU Faculty Works

3′ repair exonuclease 1 (TREX1) is a known DNA exonuclease involved in autoimmune disorders and the antiviral response. In this work, we show that TREX1 is also a RNA exonuclease. Purified TREX1 displays robust exoribonuclease activity that degrades single-stranded, but not double-stranded, RNA. TREX1-D200N, an Aicardi-Goutieres syndrome disease-causing mutant, is defective in degrading RNA. TREX1 activity is strongly inhibited by a stretch of pyrimidine residues as is a bacterial homolog, RNase T. Kinetic measurements indicate that the apparent Km of TREX1 for RNA is higher than that for DNA. Like RNase T, human TREX1 is active in degrading native tRNA …

Bicarbonate Enhances Expression Of The Endocarditis And Biofilm Associated Pilus Locus, Ebpr-Ebpabc, In Enterococcus Faecalis, Agathe Bourgogne, L Charlene Thomson, Barbara E Murray

Faculty and Staff Publications

BACKGROUND: We previously identified ebpR, encoding a potential member of the AtxA/Mga transcriptional regulator family, and showed that it is important for transcriptional activation of the Enterococcus faecalis endocarditis and biofilm associated pilus operon, ebpABC. Although ebpR is not absolutely essential for ebpABC expression (100-fold reduction), its deletion led to phenotypes similar to those of an ebpABC mutant such as absence of pili at the cell surface and, consequently, reduced biofilm formation. A non-piliated ebpABC mutant has been shown to be attenuated in a rat model of endocarditis and in a murine urinary tract infection model, indicating an important participation …

Increased Myocardial Susceptibility To Repetitive Ischemia With High-Fat Diet-Induced Obesity, Geeta D Thakker, Nikolaos G Frangogiannis, Pawel T Zymek, Saumya Sharma, Joe L Raya, Philip M Barger, Heinrich Taegtmeyer, Mark L Entman, Christie M Ballantyne

Faculty and Staff Publications

Obesity and diabetes are frequently associated with cardiovascular disease. When a normal heart is subjected to brief/sublethal repetitive ischemia and reperfusion (I/R), adaptive responses are activated to preserve cardiac structure and function. These responses include but are not limited to alterations in cardiac metabolism, reduced calcium responsiveness, and induction of antioxidant enzymes. In a model of ischemic cardiomyopathy inducible by brief repetitive I/R, we hypothesized that dysregulation of these adaptive responses in diet-induced obese (DIO) mice would contribute to enhanced myocardial injury. DIO C57BL/6J mice were subjected to 15 min of daily repetitive I/R while under short-acting anesthesia, a protocol …

Coordinated Changes In Mrna Turnover, Translation, And Rna Processing Bodies In Bronchial Epithelial Cells Following Inflammatory Stimulation, Yuxin Zhai, Zhenping Zhong, Chyi-Ying A Chen, Zhenfang Xia, Ling Song, Michael R Blackburn, Ann-Bin Shyu

Faculty and Staff Publications

Bronchial epithelial cells play a pivotal role in airway inflammation, but little is known about posttranscriptional regulation of mediator gene expression during the inflammatory response in these cells. Here, we show that activation of human bronchial epithelial BEAS-2B cells by proinflammatory cytokines interleukin-4 (IL-4) and tumor necrosis factor alpha (TNF-alpha) leads to an increase in the mRNA stability of the key chemokines monocyte chemotactic protein 1 and IL-8, an elevation of the global translation rate, an increase in the levels of several proteins critical for translation, and a reduction of microRNA-mediated translational repression. Moreover, using the BEAS-2B cell system and …

Poly(A)-Binding Protein-Interacting Protein 1 Binds To Eukaryotic Translation Initiation Factor 3 To Stimulate Translation, Yvan Martineau, Mélanie C Derry, Xiaoshan Wang, Akiko Yanagiya, Juan José Berlanga, Ann-Bin Shyu, Hiroaki Imataka, Kalle Gehring, Nahum Sonenberg

Faculty and Staff Publications

Poly(A)-binding protein (PABP) stimulates translation initiation by binding simultaneously to the mRNA poly(A) tail and eukaryotic translation initiation factor 4G (eIF4G). PABP activity is regulated by PABP-interacting (Paip) proteins. Paip1 binds PABP and stimulates translation by an unknown mechanism. Here, we describe the interaction between Paip1 and eIF3, which is direct, RNA independent, and mediated via the eIF3g (p44) subunit. Stimulation of translation by Paip1 in vivo was decreased upon deletion of the N-terminal sequence containing the eIF3-binding domain and upon silencing of PABP or several eIF3 subunits. We also show the formation of ternary complexes composed of Paip1-PABP-eIF4G and …

Identification And Phenotypic Characterization Of A Second Collagen Adhesin, Scm, And Genome-Based Identification And Analysis Of 13 Other Predicted Mscramms, Including Four Distinct Pilus Loci, In Enterococcus Faecium, Jouko Sillanpää, Sreedhar R Nallapareddy, Vittal P Prakash, Xiang Qin, Magnus Höök, George M Weinstock, Barbara E Murray

Faculty and Staff Publications

Attention has recently been drawn to Enterococcus faecium because of an increasing number of nosocomial infections caused by this species and its resistance to multiple antibacterial agents. However, relatively little is known about the pathogenic determinants of this organism. We have previously identified a cell-wall-anchored collagen adhesin, Acm, produced by some isolates of E. faecium, and a secreted antigen, SagA, exhibiting broad-spectrum binding to extracellular matrix proteins. Here, we analysed the draft genome of strain TX0016 for potential microbial surface components recognizing adhesive matrix molecules (MSCRAMMs). Genome-based bioinformatics identified 22 predicted cell-wall-anchored E. faecium surface proteins (Fms), of which 15 …

Characterization Of The Inflammatory Cells In Ascending Thoracic Aortic Aneurysms In Patients With Marfan Syndrome, Familial Thoracic Aortic Aneurysms, And Sporadic Aneurysms, Rumin He, Dong-Chuan Guo, Wei Sun, Christina L Papke, Senthil Duraisamy, Anthony L Estrera, Hazim J Safi, Chul Ahn, L Maximilian Buja, Frank C Arnett, Jingwu Zhang, Yong-Jian Geng, Dianna M Milewicz

Faculty and Staff Publications

OBJECTIVE: This study sought to characterize the inflammatory infiltrate in ascending thoracic aortic aneurysm in patients with Marfan syndrome, familial thoracic aortic aneurysm, or nonfamilial thoracic aortic aneurysm.

BACKGROUND: Thoracic aortic aneurysms are associated with a pathologic lesion termed "medial degeneration," which is described as a noninflammatory lesion. Thoracic aortic aneurysms are a complication of Marfan syndrome and can be inherited in an autosomal dominant manner of familial thoracic aortic aneurysm.

METHODS: Full aortic segments were collected from patients undergoing elective repair with Marfan syndrome (n = 5), familial thoracic aortic aneurysm (n = 6), and thoracic aortic aneurysms (n …

388 A Structure Of Cytoplasmic Polyhedrosis Virus By Cryo-Electron Microscopy, Xuekui Yu, Lei Jin, Z Hong Zhou

Faculty and Staff Publications

Cytoplasmic polyhedrosis virus (CPV) is unique within the Reoviridae family in having a turreted single-layer capsid contained within polyhedrin inclusion bodies, yet being fully capable of cell entry and endogenous RNA transcription. Biochemical data have shown that the amino-terminal 79 residues of the CPV turret protein (TP) is sufficient to bring CPV or engineered proteins into the polyhedrin matrix for micro-encapsulation. Here we report the three-dimensional structure of CPV at 3.88 A resolution using single-particle cryo-electron microscopy. Our map clearly shows the turns and deep grooves of alpha-helices, the strand separation in beta-sheets, and densities for loops and many bulky …

Clinical And Microbiological Aspects Of Linezolid Resistance Mediated By The Cfr Gene Encoding A 23s Rrna Methyltransferase, Cesar A Arias, Martha Vallejo, Jinnethe Reyes, Diana Panesso, Jaime Moreno, Elizabeth Castañeda, Maria V Villegas, Barbara E Murray, John P Quinn

Faculty and Staff Publications

The cfr (chloramphenicol-florfenicol resistance) gene encodes a 23S rRNA methyltransferase that confers resistance to linezolid. Detection of linezolid resistance was evaluated in the first cfr-carrying human hospital isolate of linezolid and methicillin-resistant Staphylococcus aureus (designated MRSA CM-05) by dilution and diffusion methods (including Etest). The presence of cfr was investigated in isolates of staphylococci colonizing the patient's household contacts and clinical isolates recovered from patients in the same unit where MRSA CM-05 was isolated. Additionally, 68 chloramphenicol-resistant Colombian MRSA isolates recovered from hospitals between 2001 and 2004 were screened for the presence of the cfr gene. In addition to erm(B), …

Messenger Rna Half-Life Measurements In Mammalian Cells, Chyi-Ying A Chen, Nader Ezzeddine, Ann-Bin Shyu

Faculty and Staff Publications

The recognition of the importance of mRNA turnover in regulating eukaryotic gene expression has mandated the development of reliable, rigorous, and "user-friendly" methods to accurately measure changes in mRNA stability in mammalian cells. Frequently, mRNA stability is studied indirectly by analyzing the steady-state level of mRNA in the cytoplasm; in this case, changes in mRNA abundance are assumed to reflect only mRNA degradation, an assumption that is not always correct. Although direct measurements of mRNA decay rate can be performed with kinetic labeling techniques and transcriptional inhibitors, these techniques often introduce significant changes in cell physiology. Furthermore, many critical mechanistic …

Application Of In Vivo Induced Antigen Technology (Iviat) To Bacillus Anthracis, Sean M Rollins, Amanda Peppercorn, John S Young, Melissa Drysdale, Andrea Baresch, Margaret V Bikowski, David A Ashford, Conrad P Quinn, Martin Handfield, Jeffrey D Hillman, C Rick Lyons, Theresa M Koehler, Stephen B Calderwood, Edward T Ryan

Faculty and Staff Publications

In vivo induced antigen technology (IVIAT) is an immuno-screening technique that identifies bacterial antigens expressed during infection and not during standard in vitro culturing conditions. We applied IVIAT to Bacillus anthracis and identified PagA, seven members of a N-acetylmuramoyl-L-alanine amidase autolysin family, three P60 family lipoproteins, two transporters, spore cortex lytic protein SleB, a penicillin binding protein, a putative prophage holin, respiratory nitrate reductase NarG, and three proteins of unknown function. Using quantitative real-time PCR comparing RNA isolated from in vitro cultured B. anthracis to RNA isolated from BALB/c mice infected with virulent Ames strain B. anthracis, we confirmed induced …

Human Tob, An Antiproliferative Transcription Factor, Is A Poly(A)-Binding Protein-Dependent Positive Regulator Of Cytoplasmic Mrna Deadenylation, Nader Ezzeddine, Tsung-Cheng Chang, Wenmiao Zhu, Akio Yamashita, Chyi-Ying A Chen, Zhenping Zhong, Yukiko Yamashita, Dinghai Zheng, Ann-Bin Shyu

Faculty and Staff Publications

In mammalian cells, mRNA decay begins with deadenylation, which involves two consecutive phases mediated by the PAN2-PAN3 and the CCR4-CAF1 complexes, respectively. The regulation of the critical deadenylation step and its relationship with RNA-processing bodies (P-bodies), which are thought to be a site where poly(A)-shortened mRNAs get degraded, are poorly understood. Using the Tet-Off transcriptional pulsing approach to investigate mRNA decay in mouse NIH 3T3 fibroblasts, we found that TOB, an antiproliferative transcription factor, enhances mRNA deadenylation in vivo. Results from glutathione S-transferase pull-down and coimmunoprecipitation experiments indicate that TOB can simultaneously interact with the poly(A) nuclease complex CCR4-CAF1 and …

Versatile Applications Of Transcriptional Pulsing To Study Mrna Turnover In Mammalian Cells, Chyi-Ying A Chen, Yukiko Yamashita, Tsung-Cheng Chang, Akio Yamashita, Wenmiao Zhu, Zhenping Zhong, Ann-Bin Shyu

Faculty and Staff Publications

Development of transcriptional pulsing approaches using the c-fos and Tet-off promoter systems greatly facilitated studies of mRNA turnover in mammalian cells. However, optimal protocols for these approaches vary for different cell types and/or physiological conditions, limiting their widespread application. In this study, we have further optimized transcriptional pulsing systems for different cell lines and developed new protocols to facilitate investigation of various aspects of mRNA turnover. We apply the Tet-off transcriptional pulsing strategy to investigate ARE-mediated mRNA decay in human erythroleukemic K562 cells arrested at various phases of the cell cycle by pharmacological inhibitors. This application facilitates studies of the …

Acquisition Of A Natural Resistance Gene Renders A Clinical Strain Of Methicillin-Resistant Staphylococcus Aureus Resistant To The Synthetic Antibiotic Linezolid, Seok-Ming Toh, Liqun Xiong, Cesar A Arias, Maria V Villegas, Karen Lolans, John Quinn, Alexander S Mankin

Faculty and Staff Publications

Linezolid, which targets the ribosome, is a new synthetic antibiotic that is used for treatment of infections caused by Gram-positive pathogens. Clinical resistance to linezolid, so far, has been developing only slowly and has involved exclusively target site mutations. We have discovered that linezolid resistance in a methicillin-resistant Staphylococcus aureus hospital strain from Colombia is determined by the presence of the cfr gene whose product, Cfr methyltransferase, modifies adenosine at position 2503 in 23S rRNA in the large ribosomal subunit. The molecular model of the linezolid-ribosome complex reveals localization of A2503 within the drug binding site. The natural function of …

Aldosterone-Induced Sgk1 Relieves Dot1a-Af9-Mediated Transcriptional Repression Of Epithelial Na+ Channel Alpha, Wenzheng Zhang, Xuefeng Xia, Mary Rose Reisenauer, Timo Rieg, Florian Lang, Dietmar Kuhl, Volker Vallon, Bruce C Kone

Faculty and Staff Publications

Aldosterone plays a major role in the regulation of salt balance and the pathophysiology of cardiovascular and renal diseases. Many aldosterone-regulated genes--including that encoding the epithelial Na+ channel (ENaC), a key arbiter of Na+ transport in the kidney and other epithelia--have been identified, but the mechanisms by which the hormone modifies chromatin structure and thus transcription remain unknown. We previously described the basal repression of ENaCalpha by a complex containing the histone H3 Lys79 methyltransferase disruptor of telomeric silencing alternative splice variant a (Dot1a) and the putative transcription factor ALL1-fused gene from chromosome 9 (Af9) as well as the release …

Ligand-Signaled Upregulation Of Enterococcus Faecalis Ace Transcription, A Mechanism For Modulating Host-E Faecalis Interaction, Sreedhar R Nallapareddy, Barbara E Murray

Faculty and Staff Publications

Enterococcus faecalis, the third most frequent cause of bacterial endocarditis, appears to be equipped with diverse surface-associated proteins showing structural-fold similarity to the immunoglobulin-fold family of staphylococcal adhesins. Among the putative E. faecalis surface proteins, the previously characterized adhesin Ace, which shows specific binding to collagen and laminin, was detectable in surface protein preparations only after growth at 46 degrees C, mirroring the finding that adherence was observed in 46 degrees C, but not 37 degrees C, grown E. faecalis cultures. To elucidate the influence of different growth and host parameters on ace expression, we investigated ace expression using E. …

Comparison Of Og1rf And An Isogenic Fsrb Deletion Mutant By Transcriptional Analysis: The Fsr System Of Enterococcus Faecalis Is More Than The Activator Of Gelatinase And Serine Protease, Agathe Bourgogne, Susan G Hilsenbeck, Gary M Dunny, Barbara E Murray

Faculty and Staff Publications

The FsrABC system of Enterococcus faecalis controls the expression of gelatinase and a serine protease via a quorum-sensing mechanism, and recent studies suggest that the Fsr system may also regulate other genes important for virulence. To investigate the possibility that Fsr influences the expression of additional genes, we used transcriptional profiling, with microarrays based on the E. faecalis strain V583 sequence, to compare the E. faecalis strain OG1RF with its isogenic mutant, TX5266, an fsrB deletion mutant. We found that the presence of an intact fsrB influences expression of numerous genes throughout the growth phases tested, namely, late log to …