bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epstein-Barr Virus LMP-1 Natural Sequence Variants Differ in Their Potential To Activate Cellular Signaling Pathways
Authors: Fielding Ceri A. , Sandvej Kristian , Mehl Anja , Brennan Paul , Jones Matthew , Rowe Martin 
Published: July 2002

ABSTRACTThe latent membrane protein 1 (LMP-1) oncogene of Epstein-Barr virus (EBV) is believed to contribute to the development of many EBV-associated tumors, and there is evidence that sequence variation can affect some functions of LMP-1. Most studies have been restricted to the prototype B95.8 LMP-1 gene and genes isolated from EBV of nasopharyngeal carcinoma (NPC) patients. Here, we analyzed the signaling functions of LMP-1 from a panel of nine EBV isolates, including representatives of four defined groups of European LMP-1 variants (groups A to D [K. Sandvej, J. W. Gratama, M. Munch, X. G. Zhou, R. L. Bolhuis, B. S. Andresen, N. Gregersen, and S. Hamilton-Dutoit, Blood 90:323–330, 1997]) and Chinese NPC-derived LMP-1. Chinese and group D variants activated the transcription factor NF-κB two- to threefold more efficiently than B95.8 LMP-1, while Chinese, group B, and group D variants similarly activated activator protein 1 (AP-1) transcription more efficiently than did B95.8 LMP-1. However, there were no amino acid substitutions in the core binding regions for tumor necrosis factor receptor-associated adapter proteins known to mediate NF-κB and AP-1 activation. In contrast, despite sequence variation in the proposed Janus kinase 3 binding region, STAT activation was remarkably constant among the panel of LMP-1 variants. Analysis of the induction of CD54 (intercellular adhesion molecule 1) protein expression by the LMP-1 variants showed differences that did not correlate with either NF-κB or AP-1. Therefore, while the defined sequence variant groups do correlate with LMP-1 function, the results highlight the fact that the relationship between sequence variation and signaling function is extremely complex. It appears unlikely that one particular amino acid substitution or deletion will define a disease-associated variant of LMP-1.
Characterization of Retrovirus-Host DNA Junctions in Cells Deficient in Nonhomologous-End Joining
Authors: Taganov Konstantin , Daniel René , Katz Richard A. , Favorova Olga , Skalka Anna Marie 
Published: July 2002

ABSTRACTFormation of stably integrated proviruses is inefficient in cells that are defective in the cellular nonhomologous end-joining (NHEJ) DNA repair pathway (R. Daniel, R. A. Katz, and A. M. Skalka, Science 284:644–647, 1999; R. Daniel, R. A. Katz, and A. M. Skalka, Mol. Cell. Biol. 21:1164–1172, 2001). However, the requirement for NHEJ function is not absolute, as 10 to 20% of infected NHEJ-deficient cells can express retrovirus- transduced reporter genes in a stable fashion. To learn more about the compensatory mechanism by which viral DNA may be incorporated into the host cell genome, we analyzed the nucleotide sequences of provirus-host DNA junctions in singly infected NHEJ-deficient cell clones. The results showed that the proviral DNA ends in all NHEJ-deficient clones had the normal 5′TG … CA3′ sequence. In addition, 14 of the 19 proviruses analyzed were flanked by a 6-bp direct repeat of host sequences, as is characteristic for avian sarcoma virus integration. These results indicate that the DNA repair pathway which compensates for loss of NHEJ in these transductants does not introduce any gross abnormalities at the provirus-host DNA junctions.
Effects of Homology Length in the Repeat Region on Minus-Strand DNA Transfer and Retroviral Replication
Authors: Dang Que , Hu Wei-Shau 
Published: July 2002

ABSTRACT
Homology between the two repeat (R) regions in the retroviral genome mediates minus-strand DNA transfer during reverse transcription. We sought to define the effects of R homology lengths on minus-strand DNA transfer. We generated five murine leukemia virus (MLV)-based vectors that contained identical sequences but different lengths of the 3′ R (3, 6, 12, 24 and 69 nucleotides [nt]); 69 nt is the full-length MLV R. After one round of replication, viral titers from the vector with a full-length downstream R were compared with viral titers generated from the other four vectors with reduced R lengths. Viral titers generated from vectors with R lengths reduced to one-third (24 nt) or one-sixth (12 nt) that of the wild type were not significantly affected; however, viral titers generated from vectors with only 3- or 6-nt homology in the R region were significantly lower. Because expression and packaging of the RNA were similar among all the vectors, the differences in the viral titers most likely reflected the impact of the homology lengths on the efficiency of minus-strand DNA transfer. The molecular nature of minus-strand DNA transfer was characterized in 63 proviruses. Precise R-to-R transfer was observed in most proviruses generated from vectors with 12-, 24-, or 69-nt homology in R, whereas aberrant transfers were predominantly used to generate proviruses from vectors with 3- or 6-nt homology. Reverse transcription using RNA transcribed from an upstream promoter, termed read-in RNA transcripts, resulted in most of the aberrant transfers. These data demonstrate that minus-strand DNA transfer is homology driven and a minimum homology length is required for accurate and efficient minus-strand DNA transfer.
Impairment of Gag-Specific CD8+T-Cell Function in Mucosal and Systemic Compartments of Simian Immunodeficiency Virus mac251- and Simian-Human Immunodeficiency Virus KU2-Infected Macaques
Authors: Hel Zdenek , Nacsa Janos , Kelsall Brian , Tsai Wen-Po , Letvin Norman , Parks Robyn Washington , Tryniszewska Elzbieta , Picker Louis , Lewis Mark G. , Edghill-Smith Yvette , Moniuszko Marcin , Pal Ranajit , Stevceva Liljana , Altman John D. , Allen Todd M. , Watkins David , Torres José V. , Berzofsky Jay A. , Belyakov Igor M. , Strober Warren , Franchini Genoveffa 
Published: July 2002

ABSTRACTThe identification of several simian immunodeficiency virus mac251 (SIVmac251) cytotoxic T-lymphocyte epitopes recognized by CD8+T cells of infected rhesus macaques carrying the Mamu-A*01 molecule and the use of peptide-major histocompatibility complex tetrameric complexes enable the study of the frequency, breadth, functionality, and distribution of virus-specific CD8+T cells in the body. To begin to address these issues, we have performed a pilot study to measure the virus-specific CD8+and CD4+T-cell response in the blood, lymph nodes, spleen, and gastrointestinal lymphoid tissues of eight Mamu-A*01-positive macaques, six of those infected with SIVmac251and two infected with the pathogenic simian-human immunodeficiency virus KU2. We focused on the analysis of the response to peptide p11C, C-M (Gag 181), since it was predominant in most tissues of all macaques. Five macaques restricted viral replication effectively, whereas the remaining three failed to control viremia and experienced a progressive loss of CD4+T cells. The frequency of the Gag 181 (p11C, C→M) immunodominant response varied among different tissues of the same animal and in the same tissues from different animals. We found that the functionality of this virus-specific CD8+T-cell population could not be assumed based on the ability to specifically bind to the Gag 181 tetramer, particularly in the mucosal tissues of some of the macaques infected by SIVmac251that were progressing to disease. Overall, the functionality of CD8+tetramer-binding T cells in tissues assessed by either measurement of cytolytic activity or the ability of these cells to produce gamma interferon or tumor necrosis factor alpha was low and was even lower in the mucosal tissue than in blood or spleen of some SIVmac251-infected animals that failed to control viremia. The data obtained in this pilot study lead to the hypothesis that disease progression may be associated with loss of virus-specific CD8+T-cell function.
Effector Function Activities of a Panel of Mutants of a Broadly Neutralizing Antibody against Human Immunodeficiency Virus Type 1
Authors: Hezareh Marjan , Hessell Ann J. , Jensen Richard C. , van de Winkel Jan G. J. , Parren Paul W. H. I. 
Published: July 2002

ABSTRACTThe human antibody immunoglobulin G1 (IgG1) b12 neutralizes a broad range of human immunodeficiency virus-type 1 (HIV-1) isolates in vitro and is able to protect against viral challenge in animal models. Neutralization of free virus, which is an antiviral activity of antibody that generally does not require the antibody Fc fragment, likely plays an important role in the protection observed. The role of Fc-mediated effector functions, which may reduce infection by inducing phagocytosis and lysis of virions and infected cells, however, is less clear. To investigate this role, we constructed a panel of IgG1 b12 mutants with point mutations in the second domain of the antibody heavy chain constant region (CH2). These mutations, as expected, did not affect gp120 binding or HIV-1 neutralization. IgG1 b12 mediated strong antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) of HIV-1-infected cells, but these activities were reduced or abrogated for the antibody mutants. Two mutants were of particular interest. K322A showed a twofold reduction in FcγR binding affinity and ADCC, while C1q binding and CDC were abolished. A double mutant (L234A, L235A) did not bind either FcγR or C1q, and both ADCC and CDC functions were abolished. In this study, we confirmed that K322 forms part of the C1q binding site in human IgG1 and plays an important role in the molecular interactions leading to complement activation. Less expectedly, we demonstrate that the lower hinge region in human IgG1 has a strong modulating effect on C1q binding and CDC. The b12 mutants K322A and L234A, L235A are useful tools for dissecting the in vivo roles of ADCC and CDC in the anti-HIV-1 activity of neutralizing antibodies.
Intracellular Trafficking of the UL11 Tegument Protein of Herpes Simplex Virus Type 1
Authors: Loomis Joshua S. , Bowzard J. Bradford , Courtney Richard J. , Wills John W. 
Published: July 2002

ABSTRACT

Growing evidence indicates that herpes simplex virus type 1 (HSV-1) acquires its final envelope in the trans-Golgi network (TGN). During the envelopment process, the viral nucleocapsid as well as the envelope and tegument proteins must arrive at this site in order to be incorporated into assembling virions. To gain a better understanding of how these proteins associate with cellular membranes and target to the correct compartment, we have been studying the intracellular trafficking properties of the small tegument protein encoded by the U
L
11 gene of HSV-1. This 96-amino-acid, myristylated protein accumulates on the cytoplasmic face of internal membranes, where it is thought to play a role in nucleocapsid envelopment and egress. When expressed in the absence of other HSV-1 proteins, the UL11 protein localizes to the Golgi apparatus, and previous deletion analyses have revealed that the membrane-trafficking information is contained within the first 49 amino acids. The goal of this study was to map the functional domains required for proper Golgi membrane localization. In addition to N-terminal myristylation, which allows for weak membrane binding, UL11 appears to be palmitylated on one or more of three consecutive N-terminal cysteines. Using membrane-pelleting experiments and confocal microscopy, we show that palmitylation of UL11 is required for both Golgi targeting specificity and strong membrane binding. Furthermore, we found that a conserved acidic cluster within the first half of UL11 is required for the recycling of this tegument protein from the plasma membrane to the Golgi apparatus. Taken together, our results demonstrate that UL11 has highly dynamic membrane-trafficking properties, which suggests that it may play multiple roles on the plasma membrane as well as on the nuclear and TGN membranes.
Increased Readthrough Transcription across the Simian Virus 5 M-F Gene Junction Leads to Growth Defects and a Global Inhibition of Viral mRNA Synthesis
Authors: Parks Griffith D. , Ward Kimberly R. , Rassa John C. 
Published: July 2002

ABSTRACT
Recombinant simian virus 5 (rSV5) mutants containing substitutions in the M-F intergenic region were generated to determine the effect of increased readthrough transcription on the paramyxovirus growth cycle. We have previously shown, using an SV5 dicistronic minigenome, that replacement of the 22-base M-F intergenic region with a foreign sequence results in a template (Rep22) that directs very high levels of M-F readthrough transcription. An rSV5 containing the Rep22 substitution grew slower and to final titers that were 50- to 80-fold lower than those of wild-type (WT) rSV5. Cells infected with the Rep22 virus produced very low levels of monocistronic M and F mRNA, consistent with the M-F readthrough phenotype. Surprisingly, Rep22 virus-infected cells also displayed a global decrease in the accumulation of viral mRNA from genes located upstream and downstream of the M-F junction, and overall viral protein synthesis was reduced. Second-site revertants of the Rep22 virus that had regained WT transcription and growth properties contained a single base substitution that increased the M gene end U tract from four to eight residues, suggesting that the growth defects originated from higher-than-normal M-F readthrough transcription. Thus, the primary growth defect for the Rep22 virus appears to be in viral RNA synthesis and not in morphogenesis. A second rSV5 virus (G14), which contained a different foreign M-F intergenic sequence, grew to similar or slightly higher titers than WT rSV5 in some cell types and produced ∼1.5- to 2-fold more mRNA and viral protein. The data support the hypothesis that inhibition of Rep22 virus growth is due to increased access by the polymerase to the 5′ end of the genome and to the resulting overexpression of L protein. We propose that the elevated naturally occurring M-F readthrough which is characteristic of many paramyxoviruses serves as a mechanism to fine-tune the level of polymerase that is optimal for virus growth.
Complete Inhibition of Tobamovirus Multiplication by Simultaneous Mutations in Two Homologous Host Genes
Authors: Yamanaka Takuya , Imai Takahiro , Satoh Rena , Kawashima Arata , Takahashi Miki , Tomita Kayo , Kubota Kenji , Meshi Tetsuo , Naito Satoshi , Ishikawa Masayuki 
Published: July 2002

ABSTRACT

The
TOM1
gene of
Arabidopsis thaliana
encodes a putative multipass transmembrane protein which is necessary for the efficient multiplication of tobamoviruses. We have previously shown that mutations severely destructive to the
TOM1
gene reduce tobamovirus multiplication to low levels but do not impair it completely. In this report, we subjected one of the
tom1
mutants (
tom1-1
) to another round of mutagenesis and isolated a new mutant which did not permit a detectable level of tobamovirus multiplication. In addition to
tom1-1
, this mutant carried a mutation referred to as
tom3-1
. Positional cloning showed that
TOM3
was one of two
TOM1
-like genes in
Arabidopsis
. Based on the similarity between the amino acid sequences of TOM1 and TOM3, together with the results of a Sos recruitment assay suggesting that both TOM1 and TOM3 bind tobamovirus-encoded replication proteins, we propose that TOM1 and TOM3 play parallel and essential roles in the replication of tobamoviruses.
Herpes Simplex Virus Tegument Protein US11 Interacts with Conventional Kinesin Heavy Chain
Authors: Diefenbach Russell J. , Miranda-Saksena Monica , Diefenbach Eve , Holland David J. , Boadle Ross A. , Armati Patricia J. , Cunningham Anthony L. 
Published: July 2002

ABSTRACT
Little is known about the mechanisms of transport of neurotropic herpesviruses, such as herpes simplex virus (HSV), varicella-zoster virus, and pseudorabies virus, within neurons. For these viruses, which replicate in the nucleus, anterograde transport from the cell body of dorsal root ganglion (DRG) neurons to the axon terminus occurs over long distances. In the case of HSV, unenveloped nucleocapsids in human DRG neurons cocultured with autologous skin were observed by immunoelectron microscopy to colocalize with conventional ubiquitous kinesin, a microtubule-dependent motor protein, in the cell body and axon during anterograde axonal transport. Subsequently, four candidate kinesin-binding structural HSV proteins were identified (VP5, VP16, VP22, and US11) using oligohistidine-tagged human ubiquitous kinesin heavy chain (uKHC) as bait. Of these viral proteins, a direct interaction between uKHC and US11 was identified. In vitro studies identified residues 867 to 894 as the US11-binding site in uKHC located within the proposed heptad repeat cargo-binding domain of uKHC. In addition, the uKHC-binding site in US11 maps to the C-terminal RNA-binding domain. US11 is consistently cotransported with kinetics similar to those of the capsid protein VP5 into the axons of dissociated rat neurons, unlike the other tegument proteins VP16 and VP22. These observations suggest a major role for the uKHC-US11 interaction in anterograde transport of unenveloped HSV nucleocapsids in axons.
Coxsackievirus B3 Replication Is Reduced by Inhibition of the Extracellular Signal-Regulated Kinase (ERK) Signaling Pathway
Authors: Luo Honglin , Yanagawa Bobby , Zhang Jingchun , Luo Zongshu , Zhang Mary , Esfandiarei Mitra , Carthy Christopher , Wilson Janet E. , Yang Decheng , McManus Bruce M. 
Published: July 2002

ABSTRACTCoxsackievirus B3 (CVB3) is the most common human pathogen for viral myocarditis. We have previously shown that the signaling protein p21rasGTPase-activating protein (RasGAP) is cleaved and that mitogen-activated protein kinases (MAPKs) ERK1/2 are activated in the late phase of CVB3 infection. However, the role of intracellular signaling pathways in CVB3-mediated myocarditis and the relative advantages of such pathways to host or virus remain largely unclear. In this study we extended our prior studies by examining the interaction between CVB3 replication and intracellular signaling pathways in HeLa cells. We observed that CVB3 infection induced a biphasic activation of ERK1/2, early transient activation versus late sustained activation, which were regulated by different mechanisms. Infection by UV-irradiated, inactivated virus capable of receptor binding and endocytosis triggered early ERK1/2 activation, but was insufficient to trigger late ERK1/2 activation. By using a general caspase inhibitor (zVAD.fmk) we further demonstrated that late ERK1/2 activation was not a result of CVB3-mediated caspase cleavage. Treatment of cells with U0126, a selective inhibitor of MAPK kinase (MEK), significantly inhibited CVB3 progeny release and decreased virus protein production. Furthermore, inhibition of ERK1/2 activation circumvented CVB3-induced apoptosis and viral protease-mediated RasGAP cleavage. Taken together, these data suggest that ERK1/2 activation is important for CVB3 replication and contributes to virus-mediated changes in host cells. Our findings demonstrate coxsackievirus takeover of a particular host signaling mechanism and uncover a prospective approach to stymie virus spread and preserve myocardial integrity.
Does early detection of otitis media with effusion prevent delayed language development?
Authors: Butler C C , MacMillan H 
Published: July 2002

OBJECTIVETo consider whether earlier detection of otitis media with effusion (OME) in asymptomatic children in the first 4 years of life prevents delayed language development.METHODSMEDLINE and other databases were searched and relevant references from articles reviewed. Critical appraisal and consensus development were in accordance with the methods of the Canadian Task Force on Preventive Health Care.RESULTSNo randomised controlled trials assessing the overall screening for OME and early intervention to prevent delay in acquiring language were identified, although one trial evaluated treatment in a screened population and found no benefit. The “analytic pathway” approach was therefore used, where evidence is evaluated for individual steps in a screening process. The evidence supporting the use of tools for early detection such as tympanometry, microtympanometry, acoustic reflectometry, and pneumatic otoscopy in the first 4 years of life is unclear. Some treatments (mucolytics, antibiotics, steroids) resulted in the short term resolution of effusions as measured by tympanometry. Ventilation tubes resolved effusions and improved hearing. Ventilation tubes in children with hearing loss associated with OME benefited children in the short term, but after 18 months there was no difference in comparison with those assigned to watchful waiting. Most prospective cohort studies that evaluated the association between OME and language development lacked adequate measurement of exposure or outcome, or suffered from attrition bias. Findings with regard to the association were inconsistent.CONCLUSIONSThere is insufficient evidence to support attempts at early detection of OME in the first 4 years of life in the asymptomatic child to prevent delayed language development.
A retrospective case-control analysis of 2002 running injuries
Authors: Taunton J E , Ryan M B , Clement D B , McKenzie D C , Lloyd-Smith D R , Zumbo B D 
Published: July 2002

Objective: To provide an extensive and up to date database for specific running related injuries, across the sexes, as seen at a primary care sports medicine facility, and to assess the relative risk for individual injuries based on investigation of selected risk factors.Methods: Patient data were recorded by doctors at the Allan McGavin Sports Medicine Centre over a two year period. They included assessment of anthropometric, training, and biomechanical information. A model was constructed (with odds ratios and their 95% confidence intervals) of possible contributing factors using a dependent variable of runners with a specific injury and comparing them with a control group of runners who experienced a different injury. Variables included in the model were: height, weight, body mass index, age, activity history, weekly activity, history of injury, and calibre of runner.Results: Most of the study group were women (54%). Some injuries occurred with a significantly higher frequency in one sex. Being less than 34 years old was reported as a risk factor across the sexes for patellofemoral pain syndrome, and in men for iliotibial band friction syndrome, patellar tendinopathy, and tibial stress syndrome. Being active for less than 8.5 years was positively associated with injury in both sexes for tibial stress syndrome; and women with a body mass index less than 21 kg/m2were at a significantly higher risk for tibial stress fractures and spinal injuries. Patellofemoral pain syndrome was the most common injury, followed by iliotibial band friction syndrome, plantar fasciitis, meniscal injuries of the knee, and tibial stress syndrome.Conclusions: Although various risk factors were shown to be positively associated with a risk for, or protection from, specific injuries, future research should include a non-injured control group and a more precise measure of weekly running distance and running experience to validate these results.