Virology Commons^™

The Highly Conserved Layer-3 Component Of The Hiv-1 Gp120 Inner Domain Is Critical For Cd4-Required Conformational Transitions, Anik Désormeaux, Mathieu Coutu, Halima Medjahed, Beatriz Pacheco, Alon Herschhorn, Christopher Gu, Shi-Hua Xiang, Youdong Mao, Joseph Sodroski, Andrés Finzi

Nebraska Center for Virology: Faculty Publications

The trimeric envelope glycoprotein (Env) of human immunodeficiency virus type 1 (HIV-1) mediates virus entry into host cells. CD4 engagement with the gp120 exterior envelope glycoprotein subunit represents the first step during HIV-1 entry. CD4-induced conformational changes in the gp120 inner domain involve three potentially flexible topological layers (layers 1, 2, and 3). Structural rearrangements between layer 1 and layer 2 have been shown to facilitate the transition of the envelope glycoprotein trimer from the unliganded to the CD4-bound state and to stabilize gp120-CD4 interaction. However, our understanding of CD4-induced conformational changes in the gp120 inner domain remains incomplete. Here, …

Analysis Of Primary Resistance Mutations To Hiv-1 Entry Inhibitors In Therapy Naive Subtype C Hiv-1 Infected Mother– Infant Pairs From Zambia, Hongyan Guo, Chang Liu, Bin Liu, Charles Wood, Xiaohong Kong

Nebraska Center for Virology: Faculty Publications

Background—Small molecular CCR5 inhibitors represent a new class of drugs for treating HIV-1 infection. The evaluation of the primary resistance mutations associated with entry inhibitors during HIV-1 perinatal transmission is required because they may have a profound impact on the clinical management in MTCT.

Objectives—To evaluate the primary resistance mutations to maraviroc and vicriviroc during perinatal transmission and analyze the sensitivity of Env derived from mother–infant pairs to maraviroc.

Study design—Nine MIPs infected by subtype C HIV-1 were recruited to analyze the prevalence and transmission of primary resistance mutations to maraviroc and vicriviroc. Moreover, Env derived from six MIPs were …

Early Childhood Infection Of Kaposi’S Sarcoma-Associated Herpesvirus In Zambian Households: A Molecular Analysis, Landon Olp, Danielle M. Shea, Maxine K. White, Clement Gondwe, Chipepo Kankasa, Charles Wood

Nebraska Center for Virology: Faculty Publications

Sub-Saharan Africa is endemic for Kaposi’s sarcoma-associated herpesvirus (KSHV) and there is a high rate of early childhood infection; however, the transmission sources are not well characterized. We examined household members as potential KSHV transmission sources to young children in the KSHV-endemic country of Zambia. To this end, we enrolled and followed Zambian households with at least one KSHV-seropositive child and collected longitudinal buccal swab samples. KSHV burden was evaluated and K1 sequences from the children were determined and analyzed for differences to K1 sequences from household members. The K1 sequences were also analyzed for evolution over time. We generated …

Towards Defining The Chloroviruses: A Genomic Journey Through A Genus Of Large Dna Viruses, Adrien Jeanniard, David D. Dunigan, James Gurnon, Irina V. Agarkova, Ming Kang, Jason Vitek, Garry Duncan, O William Mcclung, Megan Larsen, Jean-Michel Claverie, James L. Van Etten, Guillaume Blanc

Nebraska Center for Virology: Faculty Publications

Background: Giant viruses in the genus Chlorovirus (family Phycodnaviridae) infect eukaryotic green microalgae. The prototype member of the genus, Paramecium bursaria chlorella virus 1, was sequenced more than 15 years ago, and to date there are only 6 fully sequenced chloroviruses in public databases. Presented here are the draft genome sequences of 35 additional chloroviruses (287 – 348 Kb/319 – 381 predicted protein encoding genes) collected across the globe; they infect one of three different green algal species. These new data allowed us to analyze the genomic landscape of 41 chloroviruses, which revealed some remarkable features about these viruses. …

Evaluation Of Higher Plant Virus Resistance Genes In The Green Alga, Chlorella Variabilis Nc64a, During The Early Phase Of Infection With Paramecium Bursaria Chlorella Virus-1, Janet M. Rowe, David D. Dunigan, Guillaume Blanc, James R. Gurnon, Yuannan Xia, James L. Van Etten

Nebraska Center for Virology: Faculty Publications

With growing industrial interest in algae plus their critical roles in aquatic systems, the need to understand the effects of algal pathogens is increasing. We examined a model algal host–virus system, Chlorella variabilis NC64A and virus, PBCV-1. C. variabilis encodes 375 homologs to genes involved in RNA silencing and in response to virus infection in higher plants. Illumina RNA-Seq data showed that 325 of these homologs were expressed in healthy and early PBCV-1 infected (≤60 min) cells. For each of the RNA silencing genes to which homologs were found, mRNA transcripts were detected in healthy and infected cells. C. variabilis …

A Twin-Cysteine Motif In The V2 Region Of Gp120 Is Associated With Siv Envelope Trimer Stabilization, Christopher Bohl, Dane Bowder, Jesse Thompson, Levon Abrahamyan, Sandra Gonzalez-Ramirez, Youdong Mao, Joseph Sodroski, Charles Wood, Shi-Hua Xiang

Nebraska Center for Virology: Faculty Publications

The V1 and V2 variable regions of the primate immunodeficiency viruses contribute to the trimer association domain of the gp120 exterior envelope glycoprotein. A pair of V2 cysteine residues at 183 and 191 (‘‘twin cysteines’’) is present in several simian immunodeficiency viruses, human immunodeficiency virus type 2 (HIV-2) and some SIV_cpz lineages, but not in HIV-1. To examine the role of this potentially disulfide-bonded twin-cysteine motif, the cysteine residues in the SIVmac239 envelope glycoproteins were individually and pairwise substituted by alanine residues. All of the twin-cysteine mutants exhibited decreases in gp120 association with the Env trimer, membrane-fusing activity, and …

Hiv-1 Env C2-V4 Diversification In A Slow-Progressor Infant Reveals A Flat But Rugged Fitness Landscape, S. Abigail Smith, Charles Wood, John T. West

Nebraska Center for Virology: Faculty Publications

Human immunodeficiency virus type-1 (HIV-1) fitness has been associated with virus entry, a process mediated by the envelope glycoprotein (Env). We previously described Env genetic diversification in a Zambian, subtype C infected, slow-progressor child (1157i) in parallel with an evolving neutralizing antibody response. Because of the role the Variable-3 loop (V3) plays in transmission, cell tropism, neutralization sensitivity, and fitness, longitudinally isolated 1157i C2-V4 alleles were cloned into HIV-1_NL4-3-eGFP and -DsRed2 infectious molecular clones. The fluorescent reporters allowed for dual-infection competitions between all patient-derived C2-V4 chimeras to quantify the effect of V3 diversification and selection on fitness. ‘Winners’ …

‘‘Megavirales’’, A Proposed New Order For Eukaryotic Nucleocytoplasmic Large Dna Viruses, Philippe Colson, Xavier De Lamballerie, Natalya Yutin, Sassan Asgari, Yves Bigot, Dennis K. Bideshi, Xiao-Wen Cheng, Brian A. Federici, James L. Van Etten, Eugene V. Koonin, Bernard La Scola, Didier Raoult

Nebraska Center for Virology: Faculty Publications

The nucleocytoplasmic large DNA viruses (NCLDVs) comprise a monophyletic group of viruses that infect animals and diverse unicellular eukaryotes. The NCLDV group includes the families Poxviridae, Asfarviridae, Iridoviridae, Ascoviridae, Phycodnaviridae, Mimiviridae and the proposed family ‘‘Marseilleviridae’’. The family Mimiviridae includes the largest known viruses, with genomes in excess of one megabase, whereas the genome size in the other NCLDV families varies from 100 to 400 kilobase pairs. Most of the NCLDVs replicate in the cytoplasm of infected cells, within so-called virus factories. The NCLDVs share a common ancient origin, as demonstrated by evolutionary reconstructions that trace approximately 50 genes encoding …

Arbovirus Persistence And Selection Of Persistent Variants Following Chronic Infection In Aedine Mosquitoes: A Comparative Study Between Ae. Aegypti And Ae. Albopictus 30 Days Post Infection With Sindbis Virus, Zoe Leah Lyski

UNF Graduate Theses and Dissertations

In the present investigation two container breeding mosquitoes, Aedes aegypti and Aedes albopictus were exposed to Sindbis virus (SINV). Mosquitoes were proffered a viremic bloodmeal using a vertical membrane feeder in an attempt to infect females while preserving virus-gut interactions that are speculated to be responsible for amplification and selective roles encountered in nature. Cohorts of 50 mosquitoes of each species were exposed to SINV strain TR339 or EMEM in a bloodmeal and incubated in insectary conditions for 30 days. Once infected, the mosquito remains persistently infected for life, accumulating mutations in the virus RNA genome. Plaque size variants may …

Measuring Population Transmission Potential For Hiv: An Alternative Metric Of Transmission Risk In Men Who Have Sex With Men (Msm) In The Us, Colleen F. Kelley, Eli S. Rosenberg, Brandon M. O'Hara, Paula M. Frew, Travis Sanchez, John L. Peterson, Carlos Del Rio, Patrick S. Sullivan

Environmental & Global Health Faculty Research

Background Various metrics for HIV burden and treatment success [e.g. HIV prevalence, community viral load (CVL), population viral load (PVL), percent of HIV-positive persons with undetectable viral load] have important public health limitations for understanding disparities. Methods and Findings Using data from an ongoing HIV incidence cohort of black and white men who have sex with men (MSM), we propose a new metric to measure the prevalence of those at risk of transmitting HIV and illustrate its value. …See full text for complete abstract.

Microrna Mir-155 Affects Antiviral Effector And Effector Memory Cd8 T Cell Differentiation, Ching-Yi Tsai, S. Rameeza Allie, Weijun Zhang, Edward J. Usherwood

Dartmouth Scholarship

MicroRNAs are key regulators of the immune response, but their role in CD8 T cell differentiation in vivo is not known. We show that miR-155 is important in both effector and memory antiviral CD8 T cell responses. Without miR-155, there was a weaker effector response and a skewing toward memory precursor cells. At the memory stage, miR-155-deficient CD8 T cells preferentially differentiated into central memory cells and were capable of mounting a potent secondary response.

Myeloid-Derived Suppressor Cells In Murine Retrovirus-Induced Aids Inhibit T- And B-Cell Responses In Vitro That Are Used To Define The Immunodeficiency, Kathy A. Green, W. James Cook, William R. Green

Dartmouth Scholarship

Myeloid-derived suppressor cells (MDSCs) have been characterized in several disease settings, especially in many tumor systems. Compared to their involvement in tumor microenvironments, however, MDSCs have been less well studied in their responses to infectious disease processes, in particular to retroviruses that induce immunodeficiency. Here, we demonstrate for the first time the development of a highly immunosuppressive MDSC population that is dependent on infection by the LP-BM5 retrovirus, which causes murine acquired immunodeficiency. These MDSCs express a cell surface marker signature (CD11b Gr-1 Ly6C ) characteristic of monocyte-type MDSCs. Such MDSCs profoundly inhibit immune responsiveness by a cell dose- and …

Peroxiredoxin Ii Regulates Effector And Secondary Memory Cd8+ T Cell Responses, Ryan D. Michalek, Katie E. Crump, Ashley E. Weant, Elizabeth M. Hiltbold, Daniel G. Juneau, Eun-Yi Moon, Dae-Yeul Yu, Leslie B. Poole, Jason M. Grayson

Biology Faculty Articles

Reactive oxygen intermediates (ROI) generated in response to receptor stimulation play an important role in cellular responses. However, the effect of increased H₂O₂on an antigen-specific CD8⁺ T cell response was unknown. Following T cell receptor (TCR) stimulation, the expression and oxidation of peroxiredoxin II (PrdxII), a critical antioxidant enzyme, increased in CD8⁺ T cells. Deletion of PrdxII increased ROI, S phase entry, division, and death during in vitro division. During primary acute viral and bacterial infection, the number of effector CD8⁺ T cells in PrdxII-deficient mice was increased, while the number of memory …

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, …

Transcriptional Analysis Of Cervical Epithelial Cell Responses To Hiv-1, Andrew A. Block

School of Biological Sciences: Dissertations, Theses, and Student Research

Human Immunodeficiency Virus type 1 (HIV-1) infection causes a growing pandemic throughout the world, of which women comprise 51% of people who live with HIV-1, more than 60% in sub-Saharan Africa. HIV-1 infections of women are mainly acquired through female reproductive tract where cervical and vaginal epithelial cells are the first line of defense. Although HIV-1 does not directly infect epithelial cells, HIV-1 obligatorily interacts with and crosses over epithelial layer to infect susceptible target cells, mainly CD4+ T cells, in the lamina propria to initiate an infection. However, the mechanism and ramification of the interaction of HIV-1 and epithelial …

Neurosteroid-Mediated Regulation Of Brain Innate Immunity In Hiv/Aids: Dhea-S Suppresses Neurovirulence, Amber Paul, Ferdinand G. Maingat, Maria J. Polyak, Pornpun Vivithanaporn, Farshid Noorbakhsh, Samir Ahboucha, Glen B. Baker, Keir Pearson, Christopher Power

Publications

Neurosteroids are cholesterol-derived molecules synthesized within the brain, which exert trophic and protective actions. Infection by human and feline immunodeficiency viruses (HIV and FIV, respectively) causes neuroinflammation and neurodegeneration, leading to neurological deficits. Secretion of neuroinflammatory host and viral factors by glia and infiltrating leukocytes mediates the principal neuropathogenic mechanisms during, although the effect of neurosteroids on these processes is unknown. We investigated the interactions between neurosteroid mediated effects and lentivirus infection outcomes. Analyses of HIV-infected uninfected human brains disclosed a reduction in neurosteroid synthesis enzyme expression. Human neurons exposed to supernatants from HIV macrophages exhibited suppressed enzyme expression without …

Differential Virus Host-Ranges Of The Fuselloviridae Of Hyperthermophilic Archaea: Implications For Evolution In Extreme Environments, Ruben M. Ceballos, Caleb D. Marceau, Joshua O. Marceau, Steven Morris, Adam J. Clore, Kenneth M. Stedman

Biology Faculty Publications and Presentations

An emerging model for investigating virus-host interactions in hyperthermophilic Archaea is the Fusellovirus-Sulfolobus system. The host, Sulfolobus, is a hyperthermophilic acidophile endemic to sulfuric hot springs worldwide. The Fuselloviruses, also known as Sulfolobus Spindle-shaped Viruses (SSVs), are "lemon" or "spindle"-shaped double-stranded DNA viruses, which are also found worldwide. Although a few studies have addressed the host-range for the type virus, Sulfolobus Spindle-shaped Virus 1 (SSV1), using common Sulfolobus strains, a comprehensive host-range study for SSV-Sulfolobus systems has not been performed. Herein, we examine six bona fide SSV strains (SSV1, SSV2, SSV3, SSVL1, SSVK1, SSVRH) and their respective infection characteristics on …

Characterization Of Binding And Fusion Efficiencies Mediated By The V1–V5 Env Derived From Transmitted And Non-Transmitted Viruses Isolated From A Perinatal Transmission Cohort From Zambia, Mackenzie Waltke

School of Biological Sciences: Dissertations, Theses, and Student Research

Human Immunodeficiency Virus Type 1 (HIV-1) is the etiological agent of acquired immunodeficiency syndrome (AIDS), which affects over 34 million people worldwide. In sub-Saharan Africa where access to antiretroviral therapies (ART) is limited, mother-to-child transmission (MTCT) rates remain high and represent a major concern in the global HIV/AIDS epidemic. Little is known about the biological properties of viruses that are transmitted perinatally, including how the biological functions of envelope (Env) influence transmissibility. Previously, transmitted viruses were found to have an advantage in replicative fitness mediated by Env V1-V5. In this study viruses derived from transmitting mother infant pairs (MIPs) were …

Identification Of Two Functional Sumo Interacting Motifs (Sims) In The Non-Structural Protein Of Influenza A Virus Ns1a, Lorellie M. Lewis, German Rosas-Acosta

COURI Symposium Abstracts, Summer 2012

We have previously shown that the non-structural protein of Influenza A virus NS1A is post-translationally modified by conjugation of the Small Ubiquitin-like MOdifier (SUMO). Our functional studies have also demonstrated that SUMO conjugation (SUMOylation) affects NS1A's ability to neutralize the cellular interferon response of the host cell and other functions associated to NS1A. Importantly, we have also shown that influenza infections trigger a global increase in cellular SUMOylation and have recently demonstrated that such an increase is mediated by NS1A. This observation led us to investigate the molecular mechanism endowing NS1A with the ability to increase global cellular SUMOylation. Sequence …

Assessment Of A Microbicide Candidate Among A Diverse Cohort Of Urban Southern Us Women And Their Male Sexual Partners, Paula M. Frew, Kimberly Parker, Takeia Horton, Brooke Hixson, Lisa Flowers, Frances Priddy, Lisa Grohskopf, Christine Mauck, Kimberly Workowski

Environmental & Global Health Faculty Research

Background: This mixed methods study reports on product acceptance from a Phase I clinical trial of a candidate non-nucleoside reverse transcriptase inhibitor (NNRTI) vaginal microbicide product (UC781). The product was evaluated in the context of a Phase I clinical trial in an area characterized by high HIV prevalence among minority women. The findings will inform the development of an acceptable microbicide that will address the needs of diverse women and their partners. Methods: This is a mixed methods study of 34 racially and ethnically diverse female participants and 10 male partners in Atlanta, Georgia. Chi-square tests for marginal homogeneity and …