bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vaccinia Virus Nonstructural Protein Encoded by the A11R Gene Is Required for Formation of the Virion Membrane
Authors: Resch Wolfgang , Weisberg Andrea S. , Moss Bernard 
Published: May 2005

ABSTRACT
The vaccinia virus A11R gene has orthologs in all known poxvirus genomes, and the A11 protein has been previously reported to interact with the putative DNA packaging protein A32 in a yeast two-hybrid screen. Using antisera raised against A11 peptides, we show that the A11 protein was (i) expressed at late times with an apparent mass of 40 kDa, (ii) not incorporated into virus particles, (iii) phosphorylated independently of the viral F10 kinase, (iv) coimmunoprecipitated with A32, and (v) localized to the viral factory. To determine the role of the A11 protein and test whether it is indeed involved in DNA packaging, we constructed a recombinant vaccinia virus with an inducible A11R gene. This recombinant was dependent on inducer for single-cycle growth and plaque formation. In the absence of inducer, viral late proteins were produced at normal levels, but proteolytic processing and other posttranslational modifications of some proteins were inhibited, suggesting a block in virus particle assembly. Consistent with this observation, electron microscopy of cells infected in the absence of inducer showed virus factories with abnormal electron-dense viroplasms and intermediate density regions associated with membranes and containing the D13 protein. However, no viral membrane crescents, immature virions, or mature virions were produced. The requirement for nonvirion protein A11 in order to make normal viral membranes was an unexpected and exciting finding, since neither the origin of these membranes nor their mechanism of formation in the cytoplasm of infected cells is understood.
Influenza Type A Virus Escape Mutants Emerge In Vivo in the Presence of Antibodies to the Ectodomain of Matrix Protein 2
Authors: Zharikova Darya , Mozdzanowska Krystyna , Feng Jingqi , Zhang Manxin , Gerhard Walter 
Published: May 2005

ABSTRACTThe ectodomain of matrix protein 2 (M2e) of human influenza type A virus strains has remained remarkably conserved since 1918. Because M2e-specific immunity has been shown to decrease morbidity and mortality associated with influenza virus infection in several animal models and because natural infection and current vaccines do not appear to induce a good M2e-specific antibody (Ab) response, M2e has been considered as potential vaccine for inducing cross-reactive protection against influenza type A viruses. The high degree of structural conservation of M2e could in part be the consequence of a poor M2e-specific Ab response and thus the absence of pressure for change. To assess this possibility, we studied the course of infection in SCID mice in the presence or absence of passive M2e-specific monoclonal Abs (MAbs). We found that virus mutants with antigenic changes in M2e emerged in 65% of virus-infected mice treated with M2e-specific but not control MAbs. However, the diversity of escape mutants was highly restricted since only two types were isolated from 22 mice, one with a proline-to-leucine and the other with a proline-to-histidine interchange at amino acid position 10 of M2e. The implications of these findings for the use of M2e as a broadly protective vaccine are discussed.
Glycoprotein D Receptor-Dependent, Low-pH-Independent Endocytic Entry of Herpes Simplex Virus Type 1
Authors: Milne Richard S. B. , Nicola Anthony V. , Whitbeck J. Charles , Eisenberg Roselyn J. , Cohen Gary H. 
Published: May 2005

ABSTRACT
Two herpes simplex virus type 1 (HSV-1) entry pathways have been described: direct fusion between the virion envelope and the plasma membrane, as seen on Vero cells, and low-pH-dependent endocytosis, as seen on CHO nectin-1 and HeLa cells. In this paper, we studied HSV entry into C10 murine melanoma cells and identified a third entry pathway for this virus. During entry into C10 cells, virion envelope glycoproteins rapidly became protected from the membrane-impermeable chemical cross-linker BS3 and from proteinase K. Protection was gD receptor dependent, and the time taken to detect protected protein was proportional to the rate of virus entry. Ultrastructural examination revealed that virions attached to the surface of C10 cells were localized to membrane invaginations, whereas those on the surface of receptor-negative B78 cells were peripherally attached. Virus entry into C10 cells was energy dependent, and intracellular enveloped virions were seen within membrane-bound vesicles consistent with endocytic entry. Entry was not inhibited by bafilomycin A1 or ammonium chloride, showing that passage of the virion through a low-pH environment was not required for infection. Resistance to similar reagents should therefore not be taken as proof of HSV entry by a nonendosomal pathway. These data define a novel gD receptor-dependent acid-independent endocytic entry pathway for HSV.
Serotype-Specific Reorganization of the Mre11 Complex by Adenoviral E4orf3 Proteins
Authors: Stracker Travis H. , Lee Darwin V. , Carson Christian T. , Araujo Felipe D. , Ornelles David A. , Weitzman Matthew D. 
Published: May 2005

ABSTRACT
The early transcriptional region 4 (E4) of adenovirus type 5 (Ad5) encodes gene products that modulate splicing, apoptosis, transcription, DNA replication, and repair pathways. Viruses lacking both E4orf3 and E4orf6 have a severe replication defect, partially characterized by the formation of genome concatemers. Concatemer formation is dependent upon the cellular Mre11 complex and is prevented by both the E4orf3 and E4orf6 proteins. The Mre11/Rad50/Nbs1 proteins are targeted for proteasome-mediated degradation by the Ad5 viral E1b55K/E4orf6 complex. The expression of Ad5 E4orf3 causes a redistribution of Mre11 complex members and results in their exclusion from viral replication centers. For this study, we further analyzed the interactions of E4 proteins from different adenovirus serotypes with the Mre11 complex. Analyses of infections with serotypes Ad4 and Ad12 demonstrated that the degradation of Mre11/Rad50/Nbs1 proteins is a conserved feature of the E1b55K/E4orf6 complex. Surprisingly, Nbs1 and Rad50 were localized to the replication centers of both Ad4 and Ad12 viruses prior to Mre11 complex degradation. The transfection of expression vectors for the E4orf3 proteins of Ad4 and Ad12 did not alter the localization of Mre11 complex members. The E4orf3 proteins of Ad4 and Ad12 also failed to complement defects in both concatemer formation and late protein production of a virus with a deletion of E4. These results reveal surprising differences among the highly conserved E4orf3 proteins from different serotypes in the ability to disrupt the Mre11 complex.
Live Bivalent Vaccine for Parainfluenza and Influenza Virus Infections
Authors: Maeda Yasuko , Hatta Masato , Takada Ayato , Watanabe Tokiko , Goto Hideo , Neumann Gabriele , Kawaoka Yoshihiro 
Published: May 2005

ABSTRACT
Influenza and human parainfluenza virus infections are of both medical and economical importance. Currently, inactivated vaccines provide suboptimal protection against influenza, and vaccines for human parainfluenza virus infection are not available, underscoring the need for new vaccines against these respiratory diseases. Furthermore, to reduce the burden of vaccination, the development of multivalent vaccines is highly desirable. Thus, to devise a single vaccine that would elicit immune responses against both influenza and parainfluenza viruses, we used reverse genetics to generate an influenza A virus that possesses the coding region for the hemagglutinin/neuraminidase ectodomain of parainfluenza virus instead of the influenza virus neuraminidase. The recombinant virus grew efficiently in eggs but was attenuated in mice. When intranasally immunized with the recombinant vaccine, all mice developed antibodies against both influenza and parainfluenza viruses and survived an otherwise lethal challenge with either of these viruses. This live bivalent vaccine has obvious advantages over combination vaccines, and its method of generation could, in principle, be applied in the development of a “cocktail” vaccine with efficacy against several different infectious diseases.
Receptor Binding, Fusion Inhibition, and Induction of Cross-Reactive Neutralizing Antibodies by a Soluble G Glycoprotein ofHendra Virus
Authors: Bossart Katharine N. , Crameri Gary , Dimitrov Antony S. , Mungall Bruce A. , Feng Yan-Ru , Patch Jared R. , Choudhary Anil , Wang Lin-Fa , Eaton Bryan T. , Broder Christopher C. 
Published: May 2005

ABSTRACTHendra virus(HeV) andNipah virus(NiV) are closely related emerging viruses comprising theHenipavirusgenus of theParamyxovirinae, which are distinguished by their ability to cause fatal disease in both animal and human hosts. These viruses infect cells by a pH-independent membrane fusion event mediated by their attachment (G) and fusion (F) glycoproteins. Previously, we reported on HeV- and NiV-mediated fusion activities and detailed their host-cell tropism characteristics. These studies also suggested that a common cell surface receptor, which could be destroyed by protease, was utilized by both viruses. To further characterize the G glycoprotein and its unknown receptor, soluble forms of HeV G (sG) were constructed by replacing its cytoplasmic tail and transmembrane domains with an immunoglobulin κ leader sequence coupled to either an S-peptide tag (sGS-tag) or myc-epitope tag (sGmyc-tag) to facilitate purification and detection. Expression of sG was verified in cell lysates and culture supernatants by specific affinity precipitation. Analysis of sG by size exclusion chromatography and sucrose gradient centrifugation demonstrated tetrameric, dimeric, and monomeric species, with the majority of the sG released as a disulfide-linked dimer. Immunofluorescence staining revealed that sG specifically bound to HeV and NiV infection-permissive cells but not to a nonpermissive HeLa cell line clone, suggesting that it binds to virus receptor on host cells. Preincubation of host cells with sG resulted in dose-dependent inhibition of both HeV and NiV cell fusion as well as infection by live virus. Taken together, these data indicate that sG retains important native structural features, and we further demonstrate that administration of sG to rabbits can elicit a potent cross-reactive neutralizing antibody response against infectious HeV and NiV. This HeV sG glycoprotein will be exceedingly useful for structural studies, receptor identification strategies, and vaccine development goals for these important emerging viral agents.
Norovirus and Histo-Blood Group Antigens: Demonstration of a Wide Spectrum of Strain Specificities and Classification of Two Major Binding Groups among Multiple Binding Patterns
Authors: Huang Pengwei , Farkas Tibor , Zhong Weiming , Tan Ming , Thornton Scott , Morrow Ardythe L. , Jiang Xi 
Published: May 2005

ABSTRACT
Noroviruses, an important cause of acute gastroenteritis, have been found to recognize human histo-blood group antigens (HBGAs) as receptors. Four strain-specific binding patterns to HBGAs have been described in our previous report. In this study, we have extended the binding patterns to seven based on 14 noroviruses examined. The oligosaccharide-based assays revealed additional epitopes that were not detected by the saliva-based assays. The seven patterns have been classified into two groups according to their interactions with three major epitopes (A/B, H, and Lewis) of human HBGAs: the A/B-binding group and the Lewis-binding group. Strains in the A/B binding group recognize the A and/or B and H antigens, but not the Lewis antigens, while strains in the Lewis-binding group react only to the Lewis and/or H antigens. This classification also resulted in a model of the norovirus/HBGA interaction. Phylogenetic analyses showed that strains with identical or closely related binding patterns tend to be clustered, but strains in both binding group can be found in both genogroups I and II. Our results suggest that noroviruses have a wide spectrum of host range and that human HBGAs play an important role in norovirus evolution. The high polymorphism of the human HBGA system, the involvement of multiple epitopes, and the typical protein/carbohydrate interaction between norovirus VLPs and HBGAs provide an explanation for the virus-ligand binding diversities.
Identification of an Interacting Coat-External Scaffolding Protein Domain Required for both the Initiation of φX174 Procapsid Morphogenesis and the Completion of DNA Packaging
Authors: Uchiyama Asako , Fane Bentley A. 
Published: May 2005

ABSTRACT

The φX174 external scaffolding protein D mediates the assembly of coat protein pentamers into procapsids. There are four external scaffolding subunits per coat protein. Organized as pairs of asymmetric dimers, the arrangement is unrelated to quasi-equivalence. The external scaffolding protein contains seven α-helices. The protein's core, α-helices 2 to 6, mediates the vast majority of intra- and interdimer contacts and is strongly conserved in all
Microviridae
(canonical members are φX174, G4, and α3) external scaffolding proteins. On the other hand, the primary sequences of the first α-helices have diverged. The results of previous studies with α3/φX174 chimeric external scaffolding proteins suggest that α-helix 1 may act as a substrate specificity domain, mediating the initial coat scaffolding protein recognition in a species-specific manner. However, the low sequence conservation between the two phages impeded genetic analyses. In an effort to elucidate a more mechanistic model, chimeric external scaffolding proteins were constructed between the more closely related phages G4 and φX174. The results of biochemical analyses indicate that the chimeric external scaffolding protein inhibits two morphogenetic steps: the initiation of procapsid formation and DNA packaging. φX174 mutants that can efficiently utilize the chimeric protein were isolated and characterized. The substitutions appear to suppress both morphogenetic defects and are located in threefold-related coat protein sequences that most likely form the pores in the viral procapsid. These results identify coat-external scaffolding domains needed to initiate procapsid formation and provide more evidence, albeit indirect, that the pores are the site of DNA entry during the packaging reaction.
Regulated and Liver-Specific Tamarin Alpha Interferon Gene Delivery by a Helper-Dependent Adenoviral Vector
Authors: Aurisicchio Luigi , De Tomassi Amedeo , La Monica Nicola , Ciliberto Gennaro , Traboni Cinzia , Palombo Fabio 
Published: May 2005

ABSTRACT

Gene therapy approaches based on liver-restricted and regulated alpha interferon (IFN-α) expression, recently shown to be effective in different murine hepatitis models, appear promising alternatives to inhibit hepatitis C virus (HCV) replication in patients and minimize side effects. Tamarins (
Saguinus
species) infected by GB virus B (GBV-B) are considered a valid surrogate model for hepatitis C to study the biology of HCV infection and the development of new antiviral drugs. To test the efficacy of local delivery and expression of IFN-α in this model, we have developed HD-TET-tIFN, a helper-dependent adenovirus vector expressing tamarin IFN-α (tIFN) under the control of the tetracycline-inducible transactivator rtTA2
s
-S2. Expression of tIFN was successfully induced both in vitro and in vivo in rodents by doxycycline administration with consequent activation of IFN-responsive genes. More importantly, tIFN efficiently inhibited GBV-B replicon in a Huh-7 hepatoma cell line at low HD-TET-tIFN doses. A certain degree of transcriptional control of tIFN was achieved in tamarins injected with HD-TET-tIFN, but under the conditions used in this study, infection and replication of GBV-B were only delayed and not totally abrogated upon virus challenge. Hepatic delivery and regulated expression of IFN-α appear to be a possible approach for the cure of hepatitis, but this approach requires more studies to increase its efficacy. To our knowledge, this is the first report showing a regulated gene expression in a nonhuman primate hepatitis model.
Characterization of the Tupaia Rhabdovirus Genome Reveals a Long Open Reading Frame Overlapping with P and a Novel Gene Encoding a Small Hydrophobic Protein
Authors: Springfeld Christoph , Darai Gholamreza , Cattaneo Roberto 
Published: May 2005

ABSTRACTRhabdoviruses are negative-stranded RNA viruses of the orderMononegaviralesand have been isolated from vertebrates, insects, and plants. Members of the genusLyssaviruscause the invariably fatal disease rabies, and a member of the genusVesiculovirus,Chandipura virus, has recently been associated with acute encephalitis in children. We present here the complete genome sequence and transcription map of a rhabdovirus isolated from cultivated cells of hepatocellular carcinoma tissue from a moribund tree shrew. The negative-strand genome of tupaia rhabdovirus is composed of 11,440 nucleotides and encodes six genes that are separated by one or two intergenic nucleotides. In addition to the typical rhabdovirus genes in the order N-P-M-G-L, a gene encoding a small hydrophobic putative type I transmembrane protein of approximately 11 kDa was identified between the M and G genes, and the corresponding transcript was detected in infected cells. Similar to someVesiculovirusesand manyParamyxovirinae, the P gene has a second overlapping reading frame that can be accessed by ribosomal choice and encodes a protein of 26 kDa, predicted to be the largest C protein of these virus families. Phylogenetic analyses of the tupaia rhabdovirus N and L genes show that the virus is distantly related to theVesiculoviruses,Ephemeroviruses, and the recently characterized Flanders virus and Oita virus and further extends the sequence territory occupied by animal rhabdoviruses.
Identification of a Linear Peptide Recognized by Monoclonal Antibody 2D7 Capable of Generating CCR5-Specific Antibodies with Human Immunodeficiency Virus-Neutralizing Activity
Authors: Khurana Surender , Kennedy Michael , King Lisa R. , Golding Hana 
Published: May 2005

ABSTRACT
CCR5 is the major coreceptor for human immunodeficiency virus (HIV) infection. The murine monoclonal antibody (MAb) 2D7, which recognizes a conformation-dependent epitope in the second extracellular loop of CCR5, is one of the most potent inhibitors of R5 virus cell entry. However, attempts to humanize 2D7 for in vivo human use have been unsuccessful so far. A filamentous phage library expressing random peptides was used to identify a peptide mimitope that is recognized by MAb 2D7. A synthetic peptide containing this sequence (2D7-2SK) bound to MAb 2D7 with high affinity and reversed its HIV type 1 (HIV-1) fusion inhibitory activity. The peptide contains sequence homologies to two distal regions of the second extracellular loop of human CCR5, both of which are required for MAb 2D7 binding. Rabbit anti-2D7-mimitope antibodies competed with MAb 2D7 for binding to the 2D7-2SK peptide in Biacore biosensor testing. Importantly, the rabbit anti-2D7-2SK antibodies bound to CCR5 on cells and specifically inhibited R5 (but not X4) envelope-mediated syncytium formation. These antibodies also neutralized infection of human peripheral blood mononuclear cells with R5 HIV isolates comparably to MAb 2D7. In summary, we have identified a novel peptide that closely mimics the MAb 2D7 epitope on CCR5. This peptide could be included as a potential vaccine candidate or to isolate 2D7-like human antibodies as entry inhibitors for R5 viruses.
Effects of Adeno-Associated Virus DNA Hairpin Structure on Recombination
Authors: Choi Vivian W. , Samulski R. Jude , McCarty Douglas M. 
Published: May 2005

ABSTRACT
Hairpin DNA ends are evolutionarily conserved intermediates in DNA recombination. The hairpin structures present on the ends of the adeno-associated virus (AAV) genome are substrates for recombination that give rise to persistent circular and concatemeric DNA episomes through intramolecular and intermolecular recombination, respectively. We have developed circularization-dependent and orientation-specific self-complementary AAV (scAAV) vectors as a reporter system to examine recombination events involving distinct hairpin structures, i.e., closed versus open hairpins. The results suggest that intramolecular recombination (circularization) is far more efficient than intermolecular recombination (concatemerization). Among all possible combinations of terminal repeats (TRs) involved in intermolecular recombination, the closed-closed TR structures are twice as efficient as the open-open TR substrates for recombination. In addition, both intramolecular recombination and intermolecular recombination exhibit the common dependency on specific DNA polymerases and topoisomerases. The circularization-dependent and orientation-specific scAAV vectors can serve as an efficient and controlled system for the delivery of DNA structures that mimic mammalian recombination intermediates and should be useful in assaying recombination in different experimental settings as well as elucidating the molecular mechanism of recombinant AAV genome persistence.
Induction of Murine Mucosal CCR5-Reactive Antibodies as an Anti-Human Immunodeficiency Virus Strategy
Authors: Barassi C. , Soprana E. , Pastori C. , Longhi R. , Buratti E. , Lillo F. , Marenzi C. , Lazzarin A. , Siccardi A. G. , Lopalco L. 
Published: May 2005

ABSTRACTThe genital mucosa is the main site of initial human immunodeficiency virus type 1 (HIV-1) contact with its host. In spite of repeated sexual exposure, some individuals remain seronegative, and a small fraction of them produce immunoglobulin G (IgG) and IgA autoantibodies directed against CCR5, which is probably the cause of the CCR5-minus phenotype observed in the peripheral blood mononuclear cells of these subjects. These antibodies recognize the 89-to-102 extracellular loop of CCR5 in its native conformation. The aim of this study was to induce infection-preventing mucosal anti-CCR5 autoantibodies in individuals at high risk of HIV infection. Thus, we generated chimeric immunogens containing the relevant CCR5 peptide in the context of the capsid protein of Flock House virus, a presentation system in which it is possible to engineer conformationally constrained peptide in a highly immunogenic form. Administered in mice via the systemic or mucosal route, the immunogens elicited anti-CCR5 IgG and IgA (in sera and vaginal fluids). Analogous to exposed seronegative individuals, mice producing anti-CCR5 autoantibodies express significantly reduced levels of CCR5 on the surfaces of CD4+cells from peripheral blood and vaginal washes. In vitro studies have shown that murine IgG and IgA (i) specifically bind human and mouse CD4+lymphocytes and the CCR5-transfected U87 cell line, (ii) down-regulate CCR5 expression of CD4+cells from both humans and untreated mice, (iii) inhibit Mip-1β chemotaxis of CD4+CCR5+lymphocytes, and (iv) neutralize HIV R5 strains. These data suggest that immune strategies aimed at generating anti-CCR5 antibodies at the level of the genital mucosa might be feasible and represent a strategy to induce mucosal HIV-protective immunity.