bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fate of the Inner Nuclear Membrane Protein Lamin B Receptor and Nuclear Lamins in Herpes Simplex Virus Type 1 Infection
Authors: Scott Emily S. , O'Hare Peter 
Published: July 2002

ABSTRACT

During herpesvirus egress, capsids bud through the inner nuclear membrane. Underlying this membrane is the nuclear lamina, a meshwork of intermediate filaments with which it is tightly associated. Details of alterations to the lamina and the inner nuclear membrane during infection and the mechanisms involved in capsid transport across these structures remain unclear. Here we describe the fate of key protein components of the nuclear envelope and lamina during herpes simplex virus type 1 (HSV-1) infection. We followed the distribution of the inner nuclear membrane protein lamin B receptor (LBR) and lamins A and B
2
tagged with green fluorescent protein (GFP) in live infected cells. Together with additional results from indirect immunofluorescence, our studies reveal major morphologic distortion of nuclear-rim LBR and lamins A/C, B
1
, and B
2
. By 8 h p.i., we also observed a significant redistribution of LBR-GFP to the endoplasmic reticulum, where it colocalized with a subpopulation of cytoplasmic glycoprotein B by immunofluorescence. In addition, analysis by fluorescence recovery after photobleaching reveals that LBR-GFP exhibited increased diffusional mobility within the nuclear membrane of infected cells. This is consistent with the disruption of interactions between LBR and the underlying lamina. In addition to studying stably expressed GFP-lamins by fluorescence microscopy, we studied endogenous A- and B-type lamins in infected cells by Western blotting. Both approaches reveal a loss of lamins associated with virus infection. These data indicate major disruption of the nuclear envelope and lamina of HSV-1-infected cells and are consistent with a virus-induced dismantling of the nuclear lamina, possibly in order to gain access to the inner nuclear membrane.
Glycoprotein D-Independent Infectivity of Pseudorabies Virus Results in an Alteration of In Vivo Host Range and Correlates with Mutations in Glycoproteins B and H
Authors: Schmidt Jerg , Gerdts Volker , Beyer Jörg , Klupp Barbara G. , Mettenleiter Thomas C. 
Published: July 2002

ABSTRACT

Infection of cells by herpesviruses is initiated by the interaction of viral envelope glycoproteins with cellular receptors. In the alphaherpesvirus pseudorabies virus (PrV), the causative agent of Aujeszky's disease in pigs, the essential glycoprotein D (gD) mediates secondary attachment of virions to target cells by binding to newly identified cellular receptors (R. J. Geraghty, C. Krummenacher, G. H. Cohen, R. J. Eisenberg, and P. G. Spear, Science 280:1618–1620, 1998). However, in the presence of compensatory mutations, infection can also occur in the absence of gD, as evidenced by the isolation in cell culture of an infectious gD-negative PrV mutant (PrV-gD
−
Pass) (J. Schmidt, B. G. Klupp, A. Karger, and T. C. Mettenleiter, J. Virol. 71:17–24, 1997). PrV-gD
−
Pass is replication competent with an only moderate reduction in specific infectivity but appears to bind to receptors different from those recognized by wild-type PrV (A. Karger, J. Schmidt, and T. C. Mettenleiter, J. Virol. 72:7341–7348, 1998). To analyze whether this alteration in receptor usage in vitro influences infection in vivo, the model host mouse and the natural host pig were intranasally infected with PrV-gD
−
Pass and were compared to animals infected by wild-type PrV. For mice, a comparable progress of disease was observed, and all animals infected with mutant virus died, although they exhibited a slight delay in the onset of symptoms and, correspondingly, a longer time to death. In contrast, whereas wild-type PrV-infected pigs showed clinical signs and histological and histopathological findings typical of PrV infection, no signs of disease were observed after infection with PrV-gD
−
Pass. Moreover, in these animals, virus-infected cells were not detectable by immunohistochemical staining of different organ samples and no virus could be isolated from nasal swabs. Mutations in glycoproteins B and H were found to correlate with, and probably contribute to, gD-independent infectivity. In conclusion, although PrV-gD
−
Pass is virulent in mice, it is apparently unable to infect the natural host, the pig. This altered host range in vivo correlates with a difference of receptor usage in vitro and demonstrates for the first time the importance of gD receptors in alphaherpesvirus infection of an animal host.
Identification of Genes Involved in the Host Response to Neurovirulent Alphavirus Infection
Authors: Johnston Christine , Jiang Wenxia , Chu Tearina , Levine Beth 
Published: July 2002

ABSTRACTSingle-amino-acid mutations in Sindbis virus proteins can convert clinically silent encephalitis into uniformly lethal disease. However, little is known about the host gene response during avirulent and virulent central nervous system (CNS) infections. To identify candidate host genes that modulate alphavirus neurovirulence, we utilized GeneChip Expression analysis to compare CNS gene expression in mice infected with two strains of Sindbis virus that differ by one amino acid in the E2 envelope glycoprotein. Infection with Sindbis virus, dsTE12H (E2-55 HIS), resulted in 100% mortality in 10-day-old mice, whereas no disease was observed in mice infected with dsTE12Q (E2-55 GLN). dsTE12H, compared with dsTE12Q, replicated to higher titers in mouse brain and induced more CNS apoptosis. Infection with the neurovirulent dsTE12H strain was associated with both a greater number of host genes with increased expression and greater changes in levels of host gene expression than was infection with the nonvirulent dsTE12Q strain. In particular, dsTE12H infection resulted in greater increases in the levels of mRNAs encoding chemokines, proteins involved in antigen presentation and protein degradation, complement proteins, interferon-regulated proteins, and mitochondrial proteins. At least some of these increases may be beneficial for the host, as evidenced by the demonstration that enforced expression of the antiapoptotic mitochondrial protein peripheral benzodiazepine receptor (PBR) protects neonatal mice against lethal Sindbis virus infection. Thus, our findings identify specific host genes that may play a role in the host protective or pathologic response to neurovirulent Sindbis virus infection.
Feline Pit2 Functions as a Receptor for Subgroup B Feline Leukemia Viruses
Authors: Anderson Maria M. , Lauring Adam S. , Robertson Scott , Dirks Clarissa , Overbaugh Julie 
Published: July 2002

ABSTRACT
Different subgroups of feline leukemia virus (FeLV) use different host cell receptors for entry. Subgroup A FeLV (FeLV-A) is the virus that is transmitted from cat to cat, suggesting that cells expressing the FeLV-A receptor are important targets at the earliest stages of infection. FeLV-B evolves from FeLV-A in the infected cat through acquisition of cellular sequences that are related to the FeLV envelope gene. FeLV-Bs have been shown to infect cells using the Pit1 receptor, and some variants can infect cells at a lower efficiency using Pit2. Because these observations were made using receptor proteins of human or rodent origin, the role that Pit1 and Pit2 may play in FeLV-B replication in the cat is unclear. In this study, the feline Pit receptors were cloned and tested for their ability to act as receptors for different FeLV-Bs. Some FeLV-Bs infected cells expressing feline Pit2 and feline Pit1 with equal high efficiency. Variable region A (VRA) in the putative receptor-binding domain (RBD) was a critical determinant for both feline Pit1 and feline Pit2 binding, although other domains in the RBD appear to influence how efficiently the FeLV-B surface unit can bind to feline Pit2 and promote entry via this receptor. An arginine residue at position 73 in VRA was found to be important for envelope binding to feline Pit2 but not feline Pit1. Interestingly, this arginine is not found in endogenous FeLV sequences or in recombinant viruses recovered from feline cells infected with FeLV-A. Thus, while FeLV-Bs that are able to use feline Pit2 can evolve by recombination with endogenous sequences, a subsequent point mutation during reverse transcription may be needed to generate a virus that can efficiently enter the cells using the feline Pit2 as its receptor. These studies suggest that cells expressing the feline Pit2 protein are likely to be targets for FeLV-B infection in the cat.
Caveolae Are Involved in the Trafficking of Mouse Polyomavirus Virions and Artificial VP1 Pseudocapsids toward Cell Nuclei
Authors: Richterová Zuzana , Liebl David , Horák Martin , Palková Zdena , Štokrová Jitka , Hozák Pavel , Korb Jan , Forstová Jitka 
Published: July 2002

ABSTRACT
Electron and confocal microscopy were used to observe the entry and the movement of polyomavirus virions and artificial virus-like particles (VP1 pseudocapsids) in mouse fibroblasts and epithelial cells. No visible differences in adsorption and internalization of virions and VP1 pseudocapsids (“empty” or containing DNA) were observed. Viral particles entered cells internalized in smooth monopinocytic vesicles, often in the proximity of larger, caveola-like invaginations. Both “empty” vesicles derived from caveolae and vesicles containing viral particles were stained with the anti-caveolin-1 antibody, and the two types of vesicles often fused in the cytoplasm. Colocalization of VP1 with caveolin-1 was observed during viral particle movement from the plasma membrane throughout the cytoplasm to the perinuclear area. Empty vesicles and vesicles with viral particles moved predominantly along microfilaments. Particle movement was accompanied by transient disorganization of actin stress fibers. Microfilaments decorated by the VP1 immunofluorescent signal could be seen as concentric curves, apparently along membrane structures that probably represent endoplasmic reticulum. Colocalization of VP1 with tubulin was mostly observed in areas close to the cell nuclei and on mitotic tubulin structures. By 3 h postinfection, a strong signal of the VP1 (but no viral particles) had accumulated in the proximity of nuclei, around the outer nuclear membrane. However, the vast majority of VP1 pseudocapsids did not enter the nuclei.
The
trans
Golgi Network Is Lost from Cells Infected with African Swine Fever Virus
Authors: McCrossan Mari , Windsor Miriam , Ponnambalam Sreenivasan , Armstrong John , Wileman Thomas 
Published: July 2002

ABSTRACT

The cellular secretory pathway is important during the assembly and envelopment of viruses and also controls the transport of host proteins, such as cytokines and major histocompatibility proteins, that function during the elimination of viruses by the immune system. African swine fever virus (ASFV) encodes at least 26 proteins with stretches of hydrophobic amino acids suggesting entry into the secretory pathway (R. J. Yanez, J. M. Rodriguez, M. L. Nogal, L. Yuste, C. Enriquez, J. F. Rodriguez, and E. Vinuela, Virology 208:249–278, 1995). To predict how and where these potential membrane proteins function, we have studied the integrity of the secretory pathway in cells infected with ASFV. Remarkably, ASFV caused complete loss of immunofluorescence signal for the
trans
Golgi network (TGN) marker protein TGN46 and dispersed the AP1 TGN adapter complex. Loss of TGN46 signal was not due to degradation of TGN46, suggesting redistribution of TGN46 to other membrane compartments. ASFV markedly slowed transport of cathepsin D to lysosomes, demonstrating that loss of TGN structure correlated with loss of TGN function. ASFV shows a tropism for macrophages, and it is possible that ASFV compromises TGN function to augment the activity of viral membrane proteins or to suppress the function of host immunoregulatory proteins.
Recombinant Newcastle Disease Virus as a Vaccine Vector
Authors: Nakaya Takaaki , Cros Jerome , Park Man-Seong , Nakaya Yurie , Zheng Hongyong , Sagrera Ana , Villar Enrique , Garcı́a-Sastre Adolfo , Palese Peter 
Published: July 2002

ABSTRACT
A complete cDNA clone of the Newcastle disease virus (NDV) vaccine strain Hitchner B1 was constructed, and infectious recombinant virus expressing an influenza virus hemagglutinin was generated by reverse genetics. The rescued virus induces a strong humoral antibody response against influenza virus and provides complete protection against a lethal dose of influenza virus challenge in mice, demonstrating the potential of recombinant NDV as a vaccine vector.
Characterization of Novel Simian Immunodeficiency Viruses from Red-Capped Mangabeys from Nigeria (SIVrcmNG409 and -NG411)
Authors: Beer Brigitte E. , Foley Brian T. , Kuiken Carla L. , Tooze Zena , Goeken Robert M. , Brown Charles R. , Hu Jinjie , St. Claire Marisa , Korber Bette T. , Hirsch Vanessa M. 
Published: July 2002

ABSTRACTTwo novel simian immunodeficiency virus (SIV) strains from wild-caught red-capped mangabeys (Cercocebus torquatus torquatus) from Nigeria were characterized. Sequence analysis of the fully sequenced SIV strain rcmNG411 (SIVrcmNG411) andgagandpolsequence of SIVrcmNG409 revealed that they were genetically most closely related to the recently characterized SIVrcm from Gabon (SIVrcmGB1). Thus, red-capped mangabeys from distant geographic locations harbor a common lineage of SIV. SIVrcmNG411 carried avpxgene in addition tovpr, suggesting a common evolutionary ancestor with SIVsm (from sooty mangabeys). However, SIVrcm was only marginally closer to SIVsm in that region than to any of the other lentiviruses. SIVrcm showed the highest similarity inpolwith SIVdrl, isolated from a drill, a primate that is phylogenetically distinct from mangabey monkeys, and clustered with other primate lentiviruses (primarily SIVcpz [from chimpanzees] and SIVagmSab [from African green monkeys]) discordantly in different regions of the genome, suggesting a history of recombination. Despite the genetic relationship to SIVcpz in thepolgene, SIVrcmNG411 did not replicate in chimpanzee peripheral blood mononuclear cells (PBMC), although two other viruses unrelated to SIVcpz, SIVmndGB1 (from mandrills) and SIVlhoest (from L'Hoest monkeys), were able to grow in chimpanzee PBMC. The CCR5 24-bp deletion previously described in red-capped mangabeys from Gabon was also observed in Nigerian red-capped mangabeys, and SIVrcmNG411, like SIVrcmGB1, used CCR2B and STRL33 as coreceptors for virus entry. SIVrcm, SIVsm, SIVmndGB1, and all four SIVlhoest isolates but not SIVsun (from sun-tailed monkeys) replicated efficiently in human PBMC, suggesting that the ability to infect the human host can vary within one lineage.
Small Tumor Virus Genomes Are Integrated near Nuclear Matrix Attachment Regions in Transformed Cells
Authors: Shera Katherine A. , Shera Christopher A. , McDougall James K. 
Published: July 2002

ABSTRACT
More than 15% of human cancers have a viral etiology. In benign lesions induced by the small DNA tumor viruses, viral genomes are typically maintained extrachromosomally. Malignant progression is often associated with viral integration into host cell chromatin. To study the role of viral integration in tumorigenesis, we analyzed the positions of integrated viral genomes in tumors and tumor cell lines induced by the small oncogenic viruses, including the high-risk human papillomaviruses, hepatitis B virus, simian virus 40, and human T-cell leukemia virus type 1. We show that viral integrations in tumor cells lie near cellular sequences identified as nuclear matrix attachment regions (MARs), while integrations in nonneoplastic cells show no significant correlation with these regions. In mammalian cells, the nuclear matrix functions in gene expression and DNA replication. MARs play varied but poorly understood roles in eukaryotic gene expression. Our results suggest that integrated tumor virus genomes are subject to MAR-mediated transcriptional regulation, providing insight into mechanisms of viral carcinogenesis. Furthermore, the viral oncoproteins serve as invaluable tools for the study of mechanisms controlling cellular growth. Similarly, our demonstration that integrated viral genomes may be subject to MAR-mediated transcriptional effects should facilitate elucidation of fundamental mechanisms regulating eukaryotic gene expression.
Polarity of Human Parainfluenza Virus Type 3 Infection in Polarized Human Lung Epithelial A549 Cells: Role of Microfilament and Microtubule
Authors: Bose Santanu , Malur Achut , Banerjee Amiya K. 
Published: July 2002

ABSTRACT
Human parainfluenza virus type 3 (HPIV-3) is an airborne pathogen that infects the epithelial cells of the respiratory tract. In the present study we investigated the interaction of HPIV-3 with the type II alveolar human lung polarized epithelial A549 cells. Although HPIV-3 entry and budding were bidirectional from both the apical and the basolateral domains, HPIV-3 exhibited preferential entry and release from the apical pole. While disruption of the cellular actin microfilament and microtubule by cytochalasin D and nocodazole, respectively, had no effect on virus entry, disruption of the microtubule but not the microfilament inhibited HPIV-3 release.
Characterization of Rous Sarcoma Virus Gag Particles Assembled In Vitro
Authors: Yu Fang , Joshi Swati M. , Ma Yu May , Kingston Richard L. , Simon Martha N. , Vogt Volker M. 
Published: July 2002

ABSTRACT

Purified retrovirus Gag proteins or Gag protein fragments are able to assemble into virus-like particles (VLPs) in vitro in the presence of RNA. We have examined the role of nucleic acid and of the NC domain in assembly of VLPs from a Rous sarcoma virus (RSV) Gag protein and have characterized these VLPs using transmission electron microscopy (TEM), scanning TEM (STEM), and cryoelectron microscopy (cryo-EM). RNAs of diverse sizes, single-stranded DNA oligonucleotides as small as 22 nucleotides, double-stranded DNA, and heparin all promoted efficient assembly. The percentages of nucleic acid by mass, in the VLPs varied from 5 to 8%. The mean mass of VLPs, as determined by STEM, was 6.5 × 10
7
Da for both RNA-containing and DNA oligonucleotide-containing particles, corresponding to a stoichiometry of about 1,200 protein molecules per VLP, slightly lower than the 1,500 Gag molecules estimated previously for infectious RSV. By cryo-EM, the VLPs showed the characteristic morphology of immature retroviruses, with discernible regions of high density corresponding to the two domains of the CA protein. In spherically averaged density distributions, the mean radial distance to the density corresponding to the C-terminal domain of CA was 33 nm, considerably smaller than that of equivalent human immunodeficiency virus type 1 particles. Deletions of the distal portion of NC, including the second Zn-binding motif, had little effect on assembly, but deletions including the charged residues between the two Zn-binding motifs abrogated assembly. Mutation of the cysteine and histidine residues in the first Zn-binding motif to alanine did not affect assembly, but mutation of the basic residues between the two Zn-binding motifs, or of the basic residues in the N-terminal portion of NC, abrogated assembly. Together, these findings establish VLPs as a good model for immature virions and establish a foundation for dissection of the interactions that lead to assembly.
Epitope Mapping Porcine Reproductive and Respiratory Syndrome Virus by Phage Display: the nsp2 Fragment of the Replicase Polyprotein Contains a Cluster of B-Cell Epitopes
Authors: Oleksiewicz M. B. , Bøtner A. , Toft P. , Normann P. , Storgaard T. 
Published: July 2002

ABSTRACT
We screened phage display libraries of porcine reproductive and respiratory syndrome virus (PRRSV) protein fragments with sera from experimentally infected pigs to identify linear B-cell epitopes that are commonly recognized during infection in vivo. We identified 10 linear epitope sites (ES) 11 to 53 amino acids in length. In the replicase polyprotein, a total of eight ES were identified, six of which localized to the Nsp2 replicase polyprotein processing end product. In the structural proteins, a total of two ES were identified, in the ORF3 and ORF4 minor envelope glycoproteins. The ORF4 ES was previously identified by monoclonal antibody mapping (J. J. M. Meulenberg, A. P. van Nieuwstadt, A. van Essen-Zandenbergen, and J. P. M. Langeveld, J. Virol. 71:6061–6067, 1997), but its immunogenicity had not been examined in pigs. We found that six experimentally PRRSV-infected pigs consistently had very high antibody titers against the ORF4 ES. In some animals, sera diluted 1:62,500 still gave weak positive enzyme immunoassay reactivity against the ORF4 ES. This hitherto unrecognized immunodominance likely caused phages displaying the ORF4 ES to outcompete phages displaying other ES during library screening with porcine sera and accounted for our failure to identify more than two ES in the structural genes of PRRSV. Genetic analysis showed that variable ES were also the most immunogenic in vivo. Serological analysis indicated differences in the immunoglobulin A responses between short-term and longer-term viremic pigs towards some ES. The implications of these findings for PRRSV diagnostics and immunopathogenesis are discussed.
Characterization of Endogenous Avian Leukosis Viruses in Chicken Embryonic Fibroblast Substrates Used in Production of Measles and Mumps Vaccines
Authors: Johnson Jeffrey A. , Heneine Walid 
Published: July 2002

ABSTRACT

Previous findings of low levels of reverse transcriptase (RT) activity in chick cell-derived measles and mumps vaccines showed this activity to be associated with virus particles containing RNA of both subgroup E endogenous avian leukosis viruses (ALV-E) and endogenous avian viruses (EAV). These particles originate from chicken embryonic fibroblast (CEF) substrates used for propagating vaccine strains. To better characterize vaccine-associated ALV-E, we examined the endogenous ALV proviruses (
ev
loci) present in a White Leghorn CEF substrate pool by restriction fragment length polymorphism. Five
ev
loci were detected,
ev-1, ev-3, ev-6, ev-18
, and
ev-19
. Both
ev-18
and
ev-19
can express infectious ALV-E, while
ev-1, ev-3
, and
ev-6
are defective. We analyzed the full-length sequence of
ev-1
and identified an adenosine insertion within the
pol
RT-β region at position 5026, which results in a truncated RT-β and integrase. We defined the 1,692-bp deletion in the
gag-pol
region of
ev-3
, and we found that in
ev-6
, sequences from the 5′ long terminal repeat to the 5′
pol
region were absent. Based on the sequences of the
ev
loci, RT-PCR assays were developed to examine expression of ALV-E particles (EV) in CEF supernatants. Both
ev-1
- and
ev-3
-like RNA sequences were identified, as well as two other RNA sequences with intact
pol
regions, presumably of
ev-18
and
ev-19
origin. Inoculation of susceptible quail fibroblasts with CEF culture supernatants from both 5-azacytidine-induced and noninduced CEF led to ALV infection, confirming the presence of infectious ALV-E. Our data demonstrate that both defective and nondefective
ev
loci can be present in CEF vaccine substrates and suggest that both
ev
classes may contribute to the ALV present in vaccines.