bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protection of Macaques against Pathogenic Simian/Human Immunodeficiency Virus 89.6PD by Passive Transfer of Neutralizing Antibodies
Authors: Mascola John R. , Lewis Mark G. , Stiegler Gabriela , Harris Dawn , VanCott Thomas C. , Hayes Deborah , Louder Mark K. , Brown Charles R. , Sapan Christine V. , Frankel Sarah S. , Lu Yichen , Robb Merlin L. , Katinger Hermann , Birx Deborah L. 
Published: December 2019

ABSTRACTThe role of antibody in protection against human immunodeficiency virus (HIV-1) has been difficult to study in animal models because most primary HIV-1 strains do not infect nonhuman primates. Using a chimeric simian/human immunodeficiency virus (SHIV) based on the envelope of a primary isolate (HIV-89.6), we performed passive-transfer experiments in rhesus macaques to study the role of anti-envelope antibodies in protection. Based on prior in vitro data showing neutralization synergy by antibody combinations, we evaluated HIV immune globulin (HIVIG), and human monoclonal antibodies (MAbs) 2F5 and 2G12 given alone, compared with the double combination 2F5/2G12 and the triple combination HIVIG/2F5/2G12. Antibodies were administered 24 h prior to intravenous challenge with the pathogenic SHIV-89.6PD. Six control monkeys displayed high plasma viremia, rapid CD4+-cell decline, and clinical AIDS within 14 weeks. Of six animals given HIVIG/2F5/2G12, three were completely protected; the remaining three animals became SHIV infected but displayed reduced plasma viremia and near normal CD4+-cell counts. One of three monkeys given 2F5/2G12 exhibited only transient evidence of infection; the other two had marked reductions in viral load. All monkeys that received HIVIG, 2F5, or 2G12 alone became infected and developed high-level plasma viremia. However, compared to controls, monkeys that received HIVIG or MAb 2G12 displayed a less profound drop in CD4+T cells and a more benign clinical course. These data indicate a general correlation between in vitro neutralization and protection and suggest that a vaccine that elicits neutralizing antibody should have a protective effect against HIV-1 infection or disease.
The C-Terminal Region but Not the Arg-X-Pro Repeat of Epstein-Barr Virus Protein EB2 Is Required for Its Effect on RNA Splicing and Transport
Authors: Buisson Monique , Hans Fabienne , Kusters Inca , Duran Nathalie , Sergeant Alain 
Published: December 2019

ABSTRACT

The Epstein-Barr virus BMLF1 gene product EB2 has been shown to efficiently transform immortalized Rat1 and NIH 3T3 cells, to bind RNA, and to shuttle from the nucleus to the cytoplasm. In transient-expression assays EB2 seems to affect mRNA nuclear export of intronless RNAs and pre-mRNA 3′ processing, but no direct proof of EB2 being involved in RNA processing and transport has been provided, and no specific functional domain of EB2 has been mapped. Here we significantly extend these findings and directly demonstrate that (i) EB2 inhibits the cytoplasmic accumulation of mRNAs, but only if they are generated from precursors containing weak (cryptic) 5′ splice sites, (ii) EB2 has no effect on the cytoplasmic accumulation of mRNA generated from precursors containing constitutive splice sites, and (iii) EB2 has no effect on the 3′ processing of precursor RNAs containing canonical and noncanonical cleavage-polyadenylation signals. We also show that in the presence of EB2, intron-containing and intronless RNAs accumulate in the cytoplasm. EB2 contains an Arg-X-Pro tripeptide repeated eight times, similar to that described as an RNA-binding domain in the herpes simplex virus type 1 protein US11. As glutathione
S
-transferase fusion proteins, both EB2 and the Arg-X-Pro repeat bound RNA in vitro. However, by using EB2 deletion mutants, we demonstrated that the effect of EB2 on splicing and RNA transport requires the C-terminal half of the protein but not the Arg-X-Pro repeat.
Binding of Human Immunodeficiency Virus Type 1 Gag to Membrane: Role of the Matrix Amino Terminus
Authors: Ono Akira , Freed Eric O. 
Published: December 2019

ABSTRACT

Binding of the human immunodeficiency virus type 1 (HIV-1) Gag protein precursor, Pr55
Gag
, to membrane is an indispensable step in virus assembly. Previously, we reported that a matrix (MA) residue 6 substitution (6VR) imposed a virus assembly defect similar to that observed with myristylation-defective mutants, suggesting that the 6VR change impaired membrane binding. Intriguingly, the 6VR mutation had no effect on Gag myristylation. The defective phenotype imposed by 6VR was reversed by changes at other positions in MA, including residue 97. In this study, we use several biochemical methods to demonstrate that the residue 6 mutation, as well as additional substitutions in MA amino acids 7 and 8, reduce membrane binding without affecting N-terminal myristylation. This effect is observed in the context of Pr55
Gag
, a truncated Gag containing only MA and CA, and in MA itself. The membrane binding defect imposed by the 6VR mutation is reversed by second-site changes in MA residues 20 and 97, both of which, when present alone, increase membrane binding to levels greater than those for the wild type. Both reduced and enhanced membrane binding imposed by the MA substitutions depend upon the presence of the N-terminal myristate. The results support the myristyl switch model recently proposed for the regulation of Gag membrane binding, according to which membrane binding is determined by the degree of exposure or sequestration of the N-terminal myristate moiety. Alternatively, insertion of the myristate into the lipid bilayer might be a prerequisite event for the function of other distinct MA-encoded membrane binding domains.
Characterization of Varicella-Zoster Virus Glycoprotein K (Open Reading Frame 5) and Its Role in Virus Growth
Authors: Mo Chengjun , Suen Jeffrey , Sommer Marvin , Arvin Ann 
Published: December 2019

ABSTRACT

Varicella-zoster virus (VZV) is an alphaherpesvirus that is the causative agent of chickenpox and herpes zoster. VZV open reading frame 5 (ORF5) encodes glycoprotein K (gK), which is conserved among alphaherpesviruses. While VZV gK has not been characterized, and its role in viral replication is unknown, homologs of VZV gK in herpes simplex virus type 1 (HSV-1) and pseudorabies virus (PRV) have been well studied. To identify the VZV ORF5 gene product, we raised a polyclonal antibody against a fusion protein of ORF5 codons 25 to 122 with glutathione
S
-transferase and used it to study the protein in infected cells. A 40,000-molecular-weight protein was detected in cell-free virus by Western blotting. In immunogold electron microscopic studies, VZV gK was in enveloped virions and was evenly distributed in the cytoplasm in infected cells. To determine the function of VZV gK in virus growth, a series of gK deletion mutants were constructed with VZV cosmid DNA derived from the Oka strain. Full and partial deletions in gK prevented viral replication when the gK mutant cosmids were transfected into melanoma cells. Insertion of the HSV-1 (KOS) gK gene into the endogenous VZV gK site did not compensate for the deletion of VZV gK. The replacement of VZV gK at a nonnative
Avr
II site in the VZV genome restored the phenotypic characteristics of intact recombinant Oka (rOka) virus. Moreover, gK complementing cells transfected with a full gK deletion mutant exhibited viral plaques indistinguishable from those of rOka. Our results are consistent with the studies of gK proteins of HSV-1 and PRV showing that gK is indispensable for viral replication.
CCAAT Displacement Protein Binds to and Negatively Regulates Human Papillomavirus Type 6 E6, E7, and E1 Promoters
Authors: Ai Wandong , Toussaint Esra , Roman Ann 
Published: December 2019

ABSTRACT
Expression of human papillomavirus genes increases as the target cell, the keratinocyte, differentiates. CCAAT displacement protein (CDP) is a cellular protein which has been shown in other cell types to negatively regulate gene expression in undifferentiated cells but not in differentiated cells. We have previously shown that a 66-bp purine-thymidine-rich sequence (the 66-mer) binds CDP and negatively regulates the human papillomavirus type 6 (HPV-6) E6 promoter (S. Pattison, D. G. Skalnik, and A. Roman, J. Virol. 71:2013–2022, 1997). Cotransfection experiments with a plasmid expressing luciferase from the HPV-6 E6, E7, or E1 regulatory region and a plasmid carrying the CDP gene indicate that CDP represses transcription from all three HPV-6 promoters. Using electrophoretic mobility shift assays (EMSAs), we have shown that CDP binds HPV-6 both upstream and downstream of the E6, E7, and E1 transcription initiation start sites. Furthermore, when keratinocytes were induced to differentiate, all three promoter activities increased. Consistent with this, immunoblotting and EMSAs revealed that endogenous nucleus CDP and, correspondingly, DNA binding activity decreased when keratinocytes were induced to differentiate. The elevated promoter activities were abrogated by exogenously transfected CDP. Our data demonstrate that CDP fulfills the requirement of a differentiation-dependent negative regulator that could tie the HPV life cycle to keratinocyte differentiation.
Structures of Endogenous Nonecotropic Murine Leukemia Virus (MLV) Long Terminal Repeats in Wild Mice: Implication for Evolution of MLVs
Authors: Tomonaga Keizo , Coffin John M. 
Published: December 2019

ABSTRACT

To develop a better understanding of the interaction between retroviruses and their hosts, we have investigated the polymorphism in endogenous murine leukemia proviruses (MLVs). We used genomic libraries of wild mouse DNAs and PCR to analyze genetic variation in the proviruses found in wild mouse species, including
Mus musculus
(
M. m. castaneus
,
M. m. musculus
,
M. m. molossinus
, and
M. m. domesticus
),
Mus spretus
, and
Mus spicelegus
, as well as some inbred laboratory strains. In this analysis, we detected several unique forms of sequence organization in the U3 regions of the long terminal repeats of these proviruses. The distribution of the proviruses with unique U3 structures demonstrated that xenotropic MLV-related proviruses were present only in
M. musculus
subspecies, while polytropic MLV-related proviruses were found in both
M. musculus
and
M. spretus
. Furthermore, one unique provirus from
M. spicelegus
was found to be equidistant from ecotropic provirus and nonecotropic provirus by phylogenetic analysis. This provirus, termed HEMV, was thus likely to be related to the common ancestor of these MLVs. Moreover, an ancestral type of polytropic MLV-related provirus was detected in
M. spretus
species. Despite their “ancestral” phylogenetic position, proviruses of these types are not widespread in mice, implying more-recent spread by infection rather than inheritance. These results imply that recent evolution of these proviruses involved alternating periods of replication as virus and residence in the germ line.
Mapping EBNA-1 Domains Involved in Binding to Metaphase Chromosomes
Authors: Marechal Vincent , Dehee Axelle , Chikhi-Brachet Roxane , Piolot Tristan , Coppey-Moisan Maité , Nicolas Jean-Claude 
Published: December 2019

ABSTRACT
The Epstein-Barr virus (EBV) genome can persist in dividing human B cells as multicopy circular episomes. Viral episomes replicate in synchrony with host cell DNA and are maintained at a relatively constant copy number for a long time. Only two viral elements, the replication origin OriP and the EBNA-1 protein, are required for the persistence of viral genomes during latency. EBNA-1 activates OriP during the S phase and may also contribute to the partition and/or retention of viral genomes during mitosis. Indeed, EBNA-1 has been shown to interact with mitotic chromatin. Moreover, viral genomes are noncovalently associated with metaphase chromosomes. This suggests that EBNA-1 may facilitate the anchorage of viral genomes on cellular chromosomes, thus ensuring proper partition and retention. In the present paper, we have investigated the chromosome-binding activity of EBV EBNA-1, herpesvirus papio (HVP) EBNA-1, and various derivatives of EBV EBNA-1, fused to a variant of the green fluorescent protein. The results show that binding to metaphase chromosomes is a common property of EBV and HVP EBNA-1. Further studies indicated that at least three independent domains (CBS-1, -2, and -3) mediate EBNA-1 binding to metaphase chromosomes. In agreement with the anchorage model, two of these domains mapped to a region that has been previously demonstrated to be required for the long-term persistence of OriP-containing plasmids.
Subtypes of Human Immunodeficiency Virus Type 1 and Disease Stage among Women in Nairobi, Kenya
Authors: Neilson Joel R. , John Grace C. , Carr Jean K. , Lewis Paul , Kreiss Joan K. , Jackson Stephanie , Nduati Ruth W. , Mbori-Ngacha Dorothy , Panteleeff Dana D. , Bodrug Sharon , Giachetti Christina , Bott Martha A. , Richardson Barbra A. , Bwayo Job , Ndinya-Achola Jeckoniah , Overbaugh Julie 
Published: December 2019

ABSTRACT
In sub-Saharan Africa, where the effects of human immunodeficiency virus type 1 (HIV-1) have been most devastating, there are multiple subtypes of this virus. The distribution of different subtypes within African populations is generally not linked to particular risk behaviors. Thus, Africa is an ideal setting in which to examine the diversity and mixing of viruses from different subtypes on a population basis. In this setting, it is also possible to address whether infection with a particular subtype is associated with differences in disease stage. To address these questions, we analyzed the HIV-1 subtype, plasma viral loads, and CD4 lymphocyte levels in 320 women from Nairobi, Kenya. Subtype was determined by a combination of heteroduplex mobility assays and sequence analyses of envelope genes, using geographically diverse subtype reference sequences as well as envelope sequences of known subtype from Kenya. The distribution of subtypes in this population was as follows: subtype A, 225 (70.3%); subtype D, 65 (20.5%); subtype C, 22 (6.9%); and subtype G, 1 (0.3%). Intersubtype recombinant envelope genes were detected in 2.2% of the sequences analyzed. Given that the sequences analyzed represented only a small fraction of the proviral genome, this suggests that intersubtype recombinant viral genomes may be very common in Kenya and in other parts of Africa where there are multiple subtypes. The plasma viral RNA levels were highest in women infected with subtype C virus, and women infected with subtype C virus had significantly lower CD4 lymphocyte levels than women infected with the other subtypes. Together, these data suggest that women in Kenya who are infected with subtype C viruses are at more advanced stages of immunosuppression than women infected with subtype A or D. There are at least two models to explain the data from this cross-sectional study; one is that infection with subtype C is associated with a more rapid disease progression, and the second is that subtype C represents an older epidemic in Kenya. Discriminating between these possibilities in a longitudinal study will be important for increasing our understanding of the role of specific subtypes in the transmission and pathogenesis of HIV-1.
Comparative Analysis of Evolutionary Mechanisms of the Hemagglutinin and Three Internal Protein Genes of Influenza B Virus: Multiple Cocirculating Lineages and Frequent Reassortment of the NP, M, and NS Genes
Authors: Lindstrom Stephen E. , Hiromoto Yasuaki , Nishimura Hidekazu , Saito Takehiko , Nerome Reiko , Nerome Kuniaki 
Published: December 2019

ABSTRACT
Phylogenetic profiles of the genes coding for the hemagglutinin (HA) protein, nucleoprotein (NP), matrix (M) protein, and nonstructural (NS) proteins of influenza B viruses isolated from 1940 to 1998 were analyzed in a parallel manner in order to understand the evolutionary mechanisms of these viruses. Unlike human influenza A (H3N2) viruses, the evolutionary pathways of all four genes of recent influenza B viruses revealed similar patterns of genetic divergence into two major lineages. Although evolutionary rates of the HA, NP, M, and NS genes of influenza B viruses were estimated to be generally lower than those of human influenza A viruses, genes of influenza B viruses demonstrated complex phylogenetic patterns, indicating alternative mechanisms for generation of virus variability. Topologies of the evolutionary trees of each gene were determined to be quite distinct from one another, showing that these genes were evolving in an independent manner. Furthermore, variable topologies were apparently the result of frequent genetic exchange among cocirculating epidemic viruses. Evolutionary analysis done in the present study provided further evidence for cocirculation of multiple lineages as well as sequestering and reemergence of phylogenetic lineages of the internal genes. In addition, comparison of deduced amino acid sequences revealed a novel amino acid deletion in the HA1 domain of the HA protein of recent isolates from 1998 belonging to the B/Yamagata/16/88-like lineage. It thus became apparent that, despite lower evolutionary rates, influenza B viruses were able to generate genetic diversity among circulating viruses through a combination of evolutionary mechanisms involving cocirculating lineages and genetic reassortment by which new variants with distinct gene constellations emerged.
Immunization with a Live, Attenuated Simian Immunodeficiency Virus Vaccine Leads to Restriction of Viral Diversity in Rhesus Macaques Not Protected from Pathogenic Challenge
Authors: Sodora Donald L. , Sheridan Kristine E. , Marx Preston A. , Connor Ruth I. 
Published: December 2019

ABSTRACT

Rhesus macaques immunized with simian immunodeficiency virus SIVmac239Δnef but not protected from SIVmac251 challenge were studied to determine the genetic and biological characteristics of the breakthrough viruses. Assessment of SIV genetic diversity (
env
V1-V2) revealed a reduction in the number of viral species in the immunized, unprotected macaques, compared to the number in nonimmunized controls. However, no evidence for selection of a specific V1-V2 genotype was observed, and biologically cloned isolates from the animals with breakthrough virus were similar with respect to replication kinetics and coreceptor use in vitro.
Molecular Cloning and Expression of Major Structural Protein VP1 of the Human Polyomavirus JC Virus: Formation of Virus-Like Particles Useful for Immunological and Therapeutic Studies
Authors: Goldmann Claudia , Petry Harald , Frye Stephan , Ast Oliver , Ebitsch Susanne , Jentsch Klaus-Dieter , Kaup Franz-Josef , Weber Frank , Trebst Corinna , Nisslein Thomas , Hunsmann Gerhard , Weber Thomas , Lüke Wolfgang 
Published: December 2019

ABSTRACT
The major structural viral protein, VP1, of the human polyomavirus JC virus (JCV), the causative agent of progressive multifocal leukoencephalopathy (PML), was expressed by using recombinant baculoviruses. Recombinant VP1 formed virus-like particles (VLP) with the typical morphology of empty JCV capsids. Purified VP1 VLP bind to SVG, B, and T cells, as well as to monkey kidney cells. After binding, VP1 VLP were also internalized with high efficiency and transported to the nucleus. Immunization studies revealed these particles as highly immunogenic when administered with adjuvant, while immunization without adjuvant induced no immune response. VP1 VLP hyperimmune serum inhibits binding to SVG cells and neutralizes natural JCV. Furthermore, the potential of VP1 VLP as an efficient transporter system for gene therapy was demonstrated. Exogenous DNA could be efficiently packaged into VP1 VLP, and the packaged DNA was transferred into COS-7 cells as shown by the expression of a marker gene. Thus, VP1 VLP are useful for PML vaccine development and represent a potential new transporter system for human gene therapy.
A Sodium-Dependent Neutral-Amino-Acid Transporter Mediates Infections of Feline and Baboon Endogenous Retroviruses and Simian Type D Retroviruses
Authors: Tailor Chetankumar S. , Nouri Ali , Zhao Yuan , Takeuchi Yasuhiro , Kabat David 
Published: December 2019

ABSTRACT

The type D simian retroviruses cause immunosuppression in macaques and have been reported as a presumptive opportunistic infection in a patient with AIDS. Previous evidence based on viral interference has strongly suggested that the type D simian viruses share a common but unknown cell surface receptor with three type C viruses: feline endogenous virus (RD114), baboon endogenous virus, and avian reticuloendotheliosis virus. Furthermore, the receptor gene for these viruses has been mapped to human chromosome 19q13.1–13.2. We now report the isolation and characterization of a cell surface receptor for this group of retroviruses by using a human T-lymphocyte cDNA library in a retroviral vector. Swiss mouse fibroblasts (NIH 3T3), which are naturally resistant to RD114, were transduced with the retroviral library and then challenged with an RD114-pseudotyped virus containing a dominant selectable gene for puromycin resistance. Puromycin selection yielded 12 cellular clones that were highly susceptible to a β-galactosidase-encoding lacZ(RD114) pseudotype virus. Using PCR primers specific for vector sequences, we amplified a common 2.9-kb product from 10 positive clones. Expression of the 2.9-kb cDNA in Chinese hamster ovary cells conferred susceptibility to RD114, baboon endogenous virus, and the type D simian retroviruses. The 2.9-kb cDNA predicted a protein of 541 amino acids that had 98% identity with the previously cloned human Na
+
-dependent neutral-amino-acid transporter B
o
. Accordingly, expression of the RD114 receptor in NIH 3T3 cells resulted in enhanced cellular uptake of
l
-[
3
H]alanine and
l
-[
3
H]glutamine. RNA blot (Northern) analysis suggested that the RD114 receptor is widely expressed in human tissues and cell lines, including hematopoietic cells. The human B
o
transporter gene has been previously mapped to 19q13.3, which is closely linked to the gene locus of the RD114 receptor.
Monoclonal Antibodies against the Minimal DNA-Binding Domain in the Carboxyl-Terminal Region of Human Immunodeficiency Virus Type 1 Integrase
Authors: Ishikawa Tetsuya , Okui Nobuo , Kobayashi Noriko , Sakuma Ryuta , Kitamura Tadaichi , Kitamura Yoshihiro 
Published: December 2019

ABSTRACTIntegrase of human immunodeficiency virus type 1 (HIVIN) consists of 288 amino acids, and its minimum DNA-binding domain (MDBD) (amino acids [aa] 220 to 270) is required for the integration reaction. We produced and characterized four murine monoclonal antibodies (MAbs) to the MDBD of HIVIN (strain LAI). Immunoblot and enzyme-linked immunosorbent assays with truncated HIVINs showed that those MAbs recognized sequential epitopes within the MDBD (aa 228 to 236, 237 to 252, 253 to 261, and 262 to 270). Their binding to HIVIN inhibited terminal cleavage and strand transfer activities but not disintegration activity in vitro. This collection of MAbs is useful for studying the structure and function of the MDBD by complementing mutational analyses and other biochemical studies.
The Proto-Oncogene c-
myc
Is a Direct Target Gene of Epstein-Barr Virus Nuclear Antigen 2
Authors: Kaiser Carmen , Laux Gerhard , Eick Dirk , Jochner Nicola , Bornkamm Georg W. , Kempkes Bettina 
Published: December 2019

ABSTRACT

Epstein-Barr virus (EBV) infects and transforms primary B lymphocytes in vitro. Viral infection initiates the cell cycle entry of the resting B lymphocytes. The maintenance of proliferation in the infected cells is strictly dependent on functional EBNA2. We have recently developed a conditional immortalization system for EBV by rendering the function of EBNA2, and thus proliferation of the immortalized cells, dependent on estrogen. This cellular system was used to identify early events preceding induction of proliferation. We show that LMP1 and c-
myc
are directly activated by EBNA2, indicating that all cellular factors essential for induction of these genes by EBNA2 are present in the resting cells. In contrast, induction of the cell cycle regulators cyclin D2 and cdk4 are secondary events, which require de novo protein synthesis.