bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Neuronal Host Cell Factor-Binding Protein Zhangfei Inhibits Herpes Simplex Virus Replication
Authors: Akhova Oksana , Bainbridge Matthew , Misra Vikram 
Published: November 2005

ABSTRACT
During lytic infection in epithelial cells the expression of herpes simplex virus type 1 (HSV-1) immediate-early (IE) genes is initiated by a multiprotein complex comprising the virion-associated protein VP16 and two cellular proteins, host cellular factor (HCF) and Oct-1. Oct-1 directly recognizes TAATGARAT elements in promoters of IE genes. The role of HCF is not clear. HSV-1 also infects sensory neurons innervating the site of productive infection and establishes a latent infection in these cells. It is likely that some VP16 is retained by the HSV-1 nucleocapsid as it reaches the neuronal nucleus. Its activity must therefore be suppressed for successful establishment of viral latency. Recently, we discovered an HCF-binding cellular protein called Zhangfei. Zhangfei, in an HCF-dependent manner, inhibits Luman/LZIP/CREB3, another cellular HCF-binding transcription factor. Here we show that Zhangfei is selectively expressed in human neurons. When delivered to cultured cells that do not normally express the protein, Zhangfei inhibited the ability of VP16 to activate HSV-1 IE expression. The inhibition was specific for HCF-dependent transcriptional activation by VP16, since a Gal4-VP16 chimeric protein was inhibited only on a TAATGARAT-containing promoter and not a on a Gal4-containing promoter. Zhangfei associated with VP16 and inhibited formation of the VP16-HCF-Oct-1 complex on TAATGARAT motifs. Zhangfei also suppressed HSV-1-induced expression of several cellular genes including topoisomerase IIα, suggesting that in addition to suppressing IE expression Zhangfei may have an inhibitory effect on HSV-1 DNA replication and late gene expression.
Mouse Mammary Tumor Virus Encodes a Self-Regulatory RNA Export Protein and Is a Complex Retrovirus
Authors: Mertz Jennifer A. , Simper Melissa S. , Lozano Mary M. , Payne Shelley M. , Dudley Jaquelin P. 
Published: November 2005

ABSTRACTMouse mammary tumor virus (MMTV) has been classified as a simple retrovirus with two accessory genes,dutandsag. Cloned MMTV proviruses carrying a trimethoprim (trim) cassette in the envelope gene were defective for Gag protein production and the nuclear export of unsplicedgag-polRNA. Complementation experiments indicated that atrans-acting product was responsible for the Gag defect of such mutants. Analysis of MMTV-infected cells revealed the presence of a novel, doubly spliced RNA that encodes a putative product of 301 amino acids. Overexpression of cDNA from this RNA increased Gag levels fromenvmutant proviruses or reporter gene expression from unspliced mRNAs and allowed detection of a 33-kDa protein product, which has been namedregulator ofexport of MMTVmRNA, or Rem. The Rem N terminus has motifs similar to the Rev-like export proteins of complex retroviruses, and mutation of the nuclear localization signal (NLS) abolished RNA export and detection within the nucleus. The Rem C terminus has few identifiable features, but removal of this domain increased Rem-mediated export, suggesting an autoregulatory function. A reporter vector developed from the 3′ end of the MMTV provirus was Rem responsive and required both the presence of the MMTVenv-U3 junction and a functional Crm1 pathway. The identification of a third accessory protein from a doubly spliced transcript suggests that MMTV is the first murine complex retrovirus to be documented. Manipulation of the MMTV genome may provide mouse models for human retroviral diseases, such as AIDS.
Single-Molecule Analysis of Human Immunodeficiency Virus Type 1 gp120-Receptor Interactions in Living Cells
Authors: Chang Melissa I. , Panorchan Porntula , Dobrowsky Terrence M. , Tseng Yiider , Wirtz Denis 
Published: November 2005

ABSTRACT
A quantitative description of the binding interactions between human immunodeficiency virus (HIV) type 1 envelope glycoproteins and their host cell surface receptors remains incomplete. Here, we introduce a single-molecule analysis that directly probes the binding interactions between an individual viral subunit gp120 and a single receptor CD4 and/or chemokine coreceptor CCR5 in living cells. This analysis differentiates single-molecule binding from multimolecule avidity and shows that, while the presence of CD4 is required for gp120 binding to CCR5, the force required to rupture a single gp120-coreceptor bond is significantly higher and its lifetime is much longer than those of a single gp120-receptor bond. The lifetimes of these bonds are themselves shorter than those of the P-selectin/PSGL-1 bond involved in leukocyte attachment to the endothelium bonds during an inflammation response. These results suggest an amended model of HIV entry in which, immediately after the association of gp120 to its receptor, gp120 seeks its coreceptor to rapidly form a new bond. This “bond transfer” occurs only if CCR5 is in close proximity to CD4 and CD4 is still attached to gp120. The analysis presented here may serve as a general framework to study mechanisms of receptor-mediated interactions between viral envelope proteins and host cell receptors at the single-molecule level in living cells.
Human Parainfluenza Virus Type 4 Is Incapable of Evading the Interferon-Induced Antiviral Effect
Authors: Nishio Machiko , Tsurudome Masato , Ito Morihiro , Ito Yasuhiko 
Published: November 2005

ABSTRACT

The V proteins of some paramyxoviruses have developed the ability to efficiently inactivate STAT protein function as a countermeasure for evading interferon (IFN) responses. Human parainfluenza virus type 4 (hPIV4) is one of the rubulaviruses, which are members of the family
Paramyxoviridae
, and has a V protein with a highly conserved cysteine-rich domain that is the hallmark of paramyxovirus V proteins. In order to study the function of the hPIV4 V protein, we established HeLa cells expressing the hPIV4A V protein (HeLa/FlagPIV4V). The hPIV4 V protein had no ability to reduce the level of STAT1 or STAT2, although it associated with STAT1, STAT2, DDB1, and Cul4A. It interfered with neither STAT1 and STAT2 tyrosine phosphorylation nor IFN-induced STAT nuclear accumulation. In addition, HeLa/FlagPIV4V cells are fully sensitive to both beta interferon (IFN-β) and IFN-γ, indicating that the hPIV4 V protein has no ability to block IFN-induced signaling. We further established HeLa cells expressing various chimeric proteins between the hPIV2 and hPIV4A V proteins. The lack of IFN-antagonistic activity of the hPIV4 V protein is caused by both the P/V common and V-specific domains. At least two regions (amino acids [aa] 32 to 45 and aa 143 to 164) of hPIV4 V in the P/V common domain and one region (aa 200 to 212) of the C terminus are involved in the inability to evade the IFN-induced signaling. Moreover, we established HeLa cells persistently infected with hPIV4 to make sure of the inability to escape IFN and confirmed that hPIV4 is the only paramyxovirus analyzed to date that can't evade the IFN-induced antiviral responses.
Induction of Neutralizing Antibodies against Human Immunodeficiency Virus Type 1 Primary Isolates by Gag-Env Pseudovirion Immunization
Authors: Hammonds Jason , Chen Xuemin , Fouts Timothy , DeVico Anthony , Montefiori David , Spearman Paul 
Published: November 2005

ABSTRACT
A major challenge for the development of an effective HIV vaccine is to elicit neutralizing antibodies against a broad array of primary isolates. Monomeric gp120-based vaccine approaches have not been successful in inducing this type of response, prompting a number of approaches designed to recreate the native glycoprotein complex that exists on the viral membrane. Gag-Env pseudovirions are noninfectious viruslike particles that recreate the native envelope glycoprotein structure and have the potential to generate neutralizing antibody responses against primary isolates. In this study, an inducible cell line was created in order to generate Gag-Env pseudovirions for examination of neutralizing antibody responses in guinea pigs. Unadjuvanted pseudovirions generated relatively weak anti-gp120 responses, while the use of a block copolymer water-in-oil emulsion or aluminum hydroxide combined with CpG oligodeoxynucleotides resulted in high levels of antibodies that bind to gp120. Sera from immunized animals neutralized a panel of human immunodeficiency virus (HIV) type 1 primary isolate viruses at titers that were significantly higher than that of the corresponding monomeric gp120 protein. Interpretation of these results was complicated by the occurrence of neutralizing antibodies directed against cellular (non-envelope protein) components of the pseudovirion. However, a major component of the pseudovirion-elicited antibody response was directed specifically against the HIV envelope. These results provide support for the role of pseudovirion-based vaccines in generating neutralizing antibodies against primary isolates of HIV and highlight the potential confounding role of antibodies directed at non-envelope cell surface components.
Induction of Human Immunodeficiency Virus Type 1-Specific T Cells by a Bluetongue Virus Tubule-Vectored Vaccine Prime-Recombinant Modified Virus Ankara Boost Regimen
Authors: Larke Natasha , Murphy Aileen , Wirblich Christoph , Teoh Denise , Estcourt Marie J. , McMichael Andrew J. , Roy Polly , Hanke Tomáš 
Published: November 2005

ABSTRACTIn the absence of strategies for reliable induction of antibodies broadly neutralizing human immunodeficiency virus type 1 (HIV-1), vaccine efforts have shifted toward the induction of cell-mediated immunity. Here we describe the construction and immunogenicity of novel T-cell vaccine NS1.HIVA, which delivers the HIV-1 clade A consensus-derived immunogen HIVA on the surface of tubular structures spontaneously formed by protein NS1 of bluetongue virus. We demonstrated that NS1 tubules can accommodate a protein as large as 527 amino acids without losing their self-assembly capability. When injected into BALB/c mice by several routes, chimeric NS1.HIVA tubules induced HIV-1-specific major histocompatibility complex class I-restricted T cells. These could be boosted by modified virus Ankara expressing the same immunogen and generate a memory capable of gamma interferon (IFN-γ) production, proliferation, and lysis of sensitized target cells. Induced memory T cells readily produced IFN-γ 230 days postimmunization, and upon a surrogate virus challenge, NS1.HIVA vaccine alone decreased the vaccinia virus vv.HIVA load in ovaries by 2 orders of magnitude 280 days after immunization. Thus, because of its T-cell immunogenicity and antigenic simplicity, the NS1 delivery system could serve as a priming agent for heterologous prime-boost vaccination regimens. Its usefulness in primates, including humans, remains to be determined.
A Wild Goose Metapneumovirus Containing a Large Attachment Glycoprotein Is Avirulent but Immunoprotective in Domestic Turkeys
Authors: Bennett Richard S. , LaRue Rebecca , Shaw Daniel , Yu Qingzhong , Nagaraja K. V. , Halvorson David A. , Njenga M. Kariuki 
Published: November 2005

ABSTRACT

The genomic structure and composition of an avian metapneumovirus (aMPV) recently isolated from wild Canada geese (goose 15a/01) in the United States, together with its replication, virulence, and immunogenicity in domestic turkeys, were investigated. The sizes of seven of the eight genes, sequence identity, and genome organization of goose aMPV were similar to those of turkey aMPV subtype C (aMPV/C) strains, indicating that it belonged to the subtype. However, the goose virus contained the largest attachment (G) gene of any pneumovirus or metapneumovirus, with the predicted G protein of 585 amino acids (aa) more than twice the sizes of G proteins from other subtype C viruses and human metapneumovirus and more than 170 aa larger than the G proteins from the other aMPV subtypes (subtypes A, B, and D). The large G gene resulted from a 1,015-nucleotide insertion at 18 nucleotides upstream of the termination signal of the turkey aMPV/C G gene. Three other aMPV isolates from Canada geese had similarly large G genes, whereas analysis of recent aMPV strains circulating in U.S. turkeys did not indicate the presence of the goose virus-like strain. In vitro, the goose virus replicated to levels (2 × 10
5
to 5 × 10
5
50% tissue culture infective dose) comparable to those produced by turkey aMPV/C strains. More importantly, the virus replicated efficiently in the upper respiratory tract of domestic turkeys but with no clinical signs in either day-old or 2-week-old turkeys. The virus was also horizontally transmitted to naïve birds, and turkey infections with goose 15a/01 induced production of aMPV-specific antibodies. Challenging day-old or 2-week-old turkeys vaccinated with live goose aMPV resulted in lower clinical scores in 33% of the birds, whereas the rest of the birds had no detectable clinical signs of the upper respiratory disease, suggesting that the mutant virus may be a safe and effective vaccine against aMPV infection outbreaks in commercial turkeys.
Decreased Migration of Langerhans Precursor-Like Cells in Response to Human Keratinocytes Expressing Human Papillomavirus Type 16 E6/E7 Is Related to Reduced Macrophage Inflammatory Protein-3α Production
Authors: Guess Jennifer C. , McCance Dennis J. 
Published: November 2005

ABSTRACTInfection with high-risk human papillomavirus (HPV) types, particularly types 16 and 18, contributes to 90% of cervical cancer cases. HPV infects cutaneous or mucosal epithelium, tissue that is monitored for microbial infection or damage by Langerhans cells. In lesions produced by HPV type 16, there is a reduction in numbers of immune cells, especially Langerhans cells. Langerhans precursor cells selectively express CCR6, the receptor for macrophage inflammatory protein 3α (MIP-3α), and function as potent immune responders to inflamed epithelium and initiators of the innate immune response. It has been reported that E6 and E7 of high-risk HPVs interfere with immune mediators in order to suppress the recruitment of immune cells and antiviral activities of infected cells. Here we show that, following proinflammatory stimulus, HPV-16 E6 and E7 inhibit MIP-3α transcription, resulting in suppression of the migration of immature Langerhans precursor-like cells. Interestingly, the E6 and E7 proteins from the low-risk HPV types also inhibited MIP-3α transcription. These results suggest that one mechanism by which HPV-infected cells suppress the immune response may be through the inhibition of a vital alert signal, thus contributing to the persistence of HPV infection.
Homo-Oligomerization of Marburgvirus VP35 Is Essential for Its Function in Replication and Transcription
Authors: Möller Peggy , Pariente Nonia , Klenk Hans-Dieter , Becker Stephan 
Published: November 2005

ABSTRACT
The nucleocapsid protein VP35 of Marburgvirus, a filovirus, acts as the cofactor of the viral polymerase and plays an essential role in transcription and replication of the viral RNA. VP35 forms complexes with the genome encapsidating protein NP and with the RNA-dependent RNA polymerase L. In addition, a trimeric complex had been detected in which VP35 bridges L and the nucleoprotein NP. It has been presumed that the trimeric complex represents the active polymerase bound to the nucleocapsid. Here we present evidence that a predicted coiled-coil domain between amino acids 70 and 120 of VP35 is essential and sufficient to mediate homo-oligomerization of the protein. Substitution of leucine residues 90 and 104 abolished (i) the probability to form coiled coils, (ii) homo-oligomerization, and (iii) the function of VP35 in viral RNA synthesis. Further, it was found that homo-oligomerization-negative mutants of VP35 could not bind to L. Thus, it is presumed that homo-oligomerization-negative mutants of VP35 are unable to recruit the polymerase to the NP/RNA template. In contrast, inability to homo-oligomerize did not abolish the recruitment of VP35 into inclusion bodies, which contain nucleocapsid-like structures formed by NP. Finally, transcriptionally inactive mutants of VP35 containing the functional homo-oligomerization domain displayed a dominant-negative phenotype. Inhibition of VP35 oligomerization might therefore represent a suitable target for antiviral intervention.
Skin Hyperproliferation and Susceptibility to Chemical Carcinogenesis in Transgenic Mice Expressing E6 and E7 of Human Papillomavirus Type 38
Authors: Dong Wen , Kloz Ulrich , Accardi Rosita , Caldeira Sandra , Tong Wei-Min , Wang Zhao-Qi , Jansen Lars , Dürst Matthias , Sylla Bakary S. , Gissmann Lutz , Tommasino Massimo 
Published: November 2005

ABSTRACT

The oncoproteins E6 and E7 of human papillomavirus type 38 (HPV38) display several transforming activities in vitro, including immortalization of primary human keratinocytes. To evaluate the oncogenic activities of the viral proteins in an in vivo model, we generated transgenic mice expressing HPV38 E6 and E7 under the control of the bovine homologue of the human keratin 10 (K10) promoter. Two distinct lines of HPV38 E6/E7-expressing transgenic mice that express the viral genes at different levels were obtained. In both lines, HPV38 E6 and E7 induced cellular proliferation, hyperplasia, and dysplasia in the epidermis. The rate of occurrence of these events was proportional to the levels of HPV38 E6 and E7 expression in the two transgenic lines. Exposure of the epidermis of nontransgenic mice to UV led to p21
WAF1
accumulation and cell cycle arrest. In contrast, keratinocytes from transgenic mice continued to proliferate and were not positive for p21
WAF1
, indicating that cell cycle checkpoints are altered in keratinocytes expressing the viral genes. Although the HPV38 E6/E7-expressing transgenic mice did not develop spontaneous tumors during their life span, two-stage carcinogen treatment led to a high incidence of papillomas, keratoacanthomas, and squamous-cell carcinomas in HPV38 mice compared with nontransgenic animals. Together, these data show that HPV38 E6 and E7 display transforming properties in vivo, providing further support for the role of HPV38 in carcinogenesis.
Severe Acute Respiratory Syndrome Coronavirus Group-Specific Open Reading Frames Encode Nonessential Functions for Replication in Cell Cultures and Mice
Authors: Yount Boyd , Roberts Rhonda S. , Sims Amy C. , Deming Damon , Frieman Matthew B. , Sparks Jennifer , Denison Mark R. , Davis Nancy , Baric Ralph S. 
Published: November 2005

ABSTRACT
SARS coronavirus (SARS-CoV) encodes several unique group-specific open reading frames (ORFs) relative to other known coronaviruses. To determine the significance of the SARS-CoV group-specific ORFs in virus replication in vitro and in mice, we systematically deleted five of the eight group-specific ORFs, ORF3a, OF3b, ORF6, ORF7a, and ORF7b, and characterized recombinant virus replication and gene expression in vitro. Deletion of the group-specific ORFs of SARS-CoV, either alone or in various combinations, did not dramatically influence replication efficiency in cell culture or in the levels of viral RNA synthesis. The greatest reduction in virus growth was noted following ORF3a deletion. SARS-CoV spike (S) glycoprotein does not encode a rough endoplasmic reticulum (rER)/Golgi retention signal, and it has been suggested that ORF3a interacts with and targets S glycoprotein retention in the rER/Golgi apparatus. Deletion of ORF3a did not alter subcellular localization of the S glycoprotein from distinct punctuate localization in the rER/Golgi apparatus. These data suggest that ORF3a plays little role in the targeting of S localization in the rER/Golgi apparatus. In addition, insertion of the 29-bp deletion fusing ORF8a/b into the single ORF8, noted in early-stage SARS-CoV human and civet cat isolates, had little if any impact on in vitro growth or RNA synthesis. All recombinant viruses replicated to wild-type levels in the murine model, suggesting that either the group-specific ORFs play little role in in vivo replication efficiency or that the mouse model is not of sufficient quality for discerning the role of the group-specific ORFs in disease origin and development.
Contribution of GADD45 Family Members to Cell Death Suppression by Cellular Bcl-x
L
and Cytomegalovirus vMIA
Authors: Smith Geoffrey B. , Mocarski Edward S. 
Published: November 2005

ABSTRACT

Mammalian cells and viruses encode inhibitors of programmed cell death that localize to mitochondria and suppress apoptosis initiated by a wide variety of inducers. Mutagenesis was used to probe the role of a predicted α-helical region within the hydrophobic antiapoptotic domain (AAD) of cytomegalovirus vMIA, the UL37x1 gene product. This region was found to be essential for cell death suppression activity. A screen for proteins that interacted with the AAD of functional vMIA but that failed to interact with mutants identified growth arrest and DNA damage 45 (GADD45α), a cell cycle regulatory protein activated by genotoxic stress, as a candidate cellular binding partner. GADD45α interaction required the AAD α-helical character that also dictated GADD45α-mediated enhancement of death suppression. vMIA mutants that failed to interact with GADD45α were completely nonfunctional in cell death suppression, and any of the three GADD45 family members (GADD45α, GADD45β/MyD118, or GADD45γ/OIG37/CR6/GRP17) was able to cooperate with vMIA; however, none influenced cell death when introduced into cells alone. GADD45α was found to increase vMIA protein levels comparably to treatment with protease inhibitors MG132 and ALLN. Targeted short interfering RNA knockdown of all three GADD45 family members maximally reduced vMIA activity, and this reduction was abrogated by additional GADD45α. Interestingly, GADD45 family members were also able to bind and enhance cell death suppression by Bcl-x
L
, a member of the Bcl-2 family of cell death suppressors, suggesting a direct cooperative link between apoptosis and the proteins that regulate the DNA damage response.