bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adenovirus Serotype 7 Retention in a Late Endosomal Compartment prior to Cytosol Escape Is Modulated by Fiber Protein
Authors: Miyazawa Naoki , Crystal Ronald G. , Leopold Philip L. 
Published: July 2002

ABSTRACT

The intracellular trafficking of adenovirus (Ad) subgroup B (e.g., Ad7) differs from that of subgroup C (e.g., Ad5) in that Ad5 rapidly escapes from endocytic compartments following infection whereas Ad7 accumulates in organelles. To assess the hypothesis that Ad7 is targeted to the lysosomal pathway, Ad7 and Ad5 were conjugated with fluorophores and their trafficking in A549 epithelial cells was analyzed by fluorescence microscopy. Within 1 h after infection, Ad7, but not Ad5, accumulated in the cytoplasm of A549 cells. The pH in the environment of Ad5 was nearly neutral (pH 7), while Ad7 occupied acidic compartments (pH 5) over the first 2 h with a gradual shift toward neutrality by 8 h. Ad7 partially colocalized with α
2
-macroglobulin and late endosomal and lysosomal marker proteins, including Rab7, mannose-6-phosphate receptor, and LAMP-1. The pH optimum for membrane lysis by Ad7, as well as a chimeric Ad5 capsid that expressed the Ad7 fiber (Ad5fiber7), was pH 5.5, while that for lysis by Ad5 was pH 6.0. Thus, the native trafficking pathway for Ad7 involves residence in late endosomes and lysosomes, with information encoded in the Ad7 fiber acting as a pH-dependent trigger for membrane lysis and escape to the cytosol.
GLI-2 Modulates Retroviral Gene Expression
Authors: Smith Michael J. , Gitlin Scott D. , Browning Catherine M. , Lane Brian R. , Clark Nina M. , Shah Nilesh , Rainier Shirley , Markovitz David M. 
Published: July 2002

ABSTRACT

GLI proteins are involved in the development of mice, humans, zebrafish,
Caenorhabditis elegans, Xenopus
, and
Drosophila
. While these zinc finger-containing proteins bind to TG-rich promoter elements and are known to regulate gene expression in
C. elegans
and
Drosophila
, mechanistic understanding of how regulation is mediated through naturally occurring transcriptional promoters is lacking. One isoform of human GLI-2 appears to be identical to a factor previously called Tax helper protein (THP), thus named due to its ability to interact with a TG-rich element in the human T-lymphotropic virus type 1 (HTLV-1) enhancer thought to mediate transcriptional stimulation by the Tax protein of HTLV-1. We now demonstrate that, working through its TG-rich binding site and adjacent elements, GLI-2/THP actually suppresses gene expression driven by the HTLV-1 promoter. GLI-2/THP has no effect on the HTLV-2 promoter, activates expression from the promoters of human immunodeficiency virus types 1 and (HIV-1 and -2), and stimulates HIV-1 replication. Both effective suppression and activation of gene expression and viral replication require the first of the five zinc fingers, which is not necessary for DNA binding, to be intact. Thus, not only can GLI-2/THP either activate or suppress gene expression, depending on the promoter, but the same domain (first zinc finger) mediates both effects. These findings suggest a role for GLI-2 in retroviral gene regulation and shed further light on the mechanisms by which GLI proteins regulate naturally occurring promoters.
Human Immunodeficiency Virus Type 1 Nef-Induced CD4 Cell Surface Downregulation Is Inhibited by Ikarugamycin
Authors: Luo Tianci , Fredericksen Brenda L. , Hasumi Keiji , Endo Akira , Garcia J. Victor 
Published: July 2002

ABSTRACTOne well-characterized in vitro function of Nef is its ability to remove CD4, the human immunodeficiency virus (HIV) receptor, from the cell surface. Nef accomplishes this by accelerating the internalization and degradation of CD4. Current models propose that Nef promotes CD4 internalization via an increased association of CD4 with clathrin-coated pits (CCP). Here, we investigated the effect of a naturally occurring antiprotozoan antibiotic, ikarugamycin (IKA), on CD4 cell surface expression in human monocytic cells stably expressing HIV type 1 SF2 Nef. IKA was able to efficiently restore CD4 cell surface expression in Nef-expressing cells without affecting either CD4 synthesis or Nef expression. In addition, we demonstrate that IKA is also capable of efficiently blocking CD4 down-modulation in response to phorbol myristate acetate. Our data suggest that IKA may be an efficient and useful inhibitor of CCP-dependent endocytosis.
Bacteriophage K1-5 Encodes Two Different Tail Fiber Proteins, Allowing It To Infect and Replicate on both K1 and K5 Strains of
Escherichia coli
Authors: Scholl Dean , Rogers Scott , Adhya Sankar , Merril Carl R. 
Published: July 2002

ABSTRACT

A virulent double-stranded DNA bacteriophage, ΦK1-5, has been isolated and found to be capable of infecting
Escherichia coli
strains that possess either the K1 or the K5 polysaccharide capsule. Electron micrographs show that the virion consists of a small icosohedral head with short tail spikes, similar to members of the
Podoviridae
family. DNA sequence analysis of the region encoding the tail fiber protein showed two open reading frames encoding previously characterized hydrolytic phage tail fiber proteins. The first is the K5 lyase protein gene of ΦK5, which allows this phage to specifically infect K5
E. coli
strains. A second open reading frame encodes a protein almost identical in amino acid sequence to the
N
-acetylneuraminidase (endosialidase) protein of ΦK1E, which allows this phage to specifically infect K1 strains of
E. coli
. We provide experimental evidence that mature phage particles contain both tail fiber proteins, and mutational analysis indicates that each protein can be independently inactivated. A comparison of the tail gene regions of ΦK5, ΦK1E, and ΦK1-5 shows that the genes are arranged in a modular or cassette configuration and suggests that this family of phages can broaden host range by horizontal gene transfer.
Deleterious Effects of Hepatitis Delta Virus Replication on Host Cell Proliferation
Authors: Wang David , Pearlberg Joseph , Liu Yu-Tsueng , Ganem Don 
Published: July 2002

ABSTRACT
Hepatitis delta virus (HDV) infection and spread in vivo are dependent upon coinfection by hepatitis B virus (HBV), and dual HDV/HBV infection is frequently more severe than HBV infection alone, raising the possibility that HDV infection may be deleterious to cells. Here we have examined the effects of HDV replication on the long-term growth of cultured cells. Our results show that most cells transfected with HDV cDNA do not give rise to stable cell lines expressing viral antigens or replicative intermediates; in addition, cotransfection of HDV replicons with a plasmid vector expressing a hygromycin resistance marker results in a dose-dependent impairment of hygromycin-resistant colony formation. When cells transfected with replication-competent HDV cDNA are followed prospectively, a progressive decline in viral RNA replication and a steady decrease in the proportion of cells expressing delta antigen are observed. However, in transient transfection assays, no evidence was found to link HDV replication to apoptosis or to cell cycle arrest, nor did HDV replication confer on host cells enhanced sensitivity to inducers of apoptosis. Thus, HDV replication does not appear to be acutely cytotoxic. However, in dividing cells HDV replication is associated with a subtler growth disadvantage, leading to selection in culture for cells displaying diminished HDV expression. This effect would not be expected to cause hepatitis in vivo but might contribute to impaired liver regeneration in the setting of ongoing hepatocellular injury.
Jaagsiekte Sheep Retrovirus Proviral Clone JSRV
JS7
, Derived from the JS7 Lung Tumor Cell Line, Induces Ovine Pulmonary Carcinoma and Is Integrated into the Surfactant Protein A Gene
Authors: DeMartini James C. , Bishop Jeanette V. , Allen Thomas E. , Jassim F. A. , Sharp J. Michael , de las Heras Marcelo , Voelker Dennis R. , Carlson Jonathan O. 
Published: July 2002

ABSTRACT

Ovine pulmonary carcinoma (OPC) is a contagious neoplasm of alveolar epithelial type II (ATII) or Clara cells caused by a type D/B chimeric retrovirus, jaagsiekte sheep retrovirus (JSRV). Here we report the isolation, sequencing, pathogenicity, and integration site of a JSRV provirus isolated from a sheep lung tumor cell line (JS7). The sequence of the virus was 93 to 99% identical to other JSRV isolates and contained all of the expected open reading frames. To produce virions and test its infectivity, the JS7 provirus (JSRV
JS7
) was cloned into a plasmid containing a cytomegalovirus promoter and transfected into 293T cells. After intratracheal inoculation with virions from concentrated supernatant fluid, JSRV-associated OPC lesions were found in one of four lambs, confirming that JSRV
JS7
is pathogenic. In JS7-cell DNA, the viral genome was inserted in the protein-coding region for the surfactant protein A (SP-A) gene, which is highly expressed in ATII cells, in an orientation opposite to the direction of transcription of the SP-A gene. No significant transcription was detected from either the viral or the SP-A gene promoter in the JS7 cell line at passage level 170. The oncogenic significance of the JSRV proviral insertion involving the SP-A locus in the JS7 tumor cell line is unknown.
Open Reading Frame UL26 of Human Cytomegalovirus Encodes a Novel Tegument Protein That Contains a Strong Transcriptional Activation Domain
Authors: Stamminger Thomas , Gstaiger Matthias , Weinzierl Konstanze , Lorz Kerstin , Winkler Michael , Schaffner Walter 
Published: July 2002

ABSTRACT
A selection strategy, the activator trap, was used in order to identify genes of human cytomegalovirus (HCMV) that encode strong transcriptional activation domains in mammalian cells. This approach is based on the isolation of activation domains from a GAL4 fusion library by means of selective plasmid replication, which is mediated in transfected cells by a GAL4-inducible T antigen gene. With this screening strategy, we were able to isolate two types of plasmids encoding transactivating fusion proteins from a library of random HCMV DNA inserts. One plasmid contained the exon 3 of the HCMV IE-1/2 gene region, which has previously been identified as a strong transcriptional activation domain. In the second type of plasmid, the open reading frame (ORF) UL26 of HCMV was fused to the GAL4 DNA-binding domain. By quantitative RNA mapping using S1 nuclease analysis, we were able to classify UL26 as a strong enhancer-type activation domain with no apparent homology to characterized transcriptional activators. Western blot analysis with a specific polyclonal antibody raised against a prokaryotic UL26 fusion protein revealed that two protein isoforms of 21 and 27 kDa are derived from the UL26 ORF in both infected and transfected cells. Both protein isoforms, which arise via alternative usage of two in-frame translational start codons, showed a nuclear localization and could be detected as early as 6 h after infection of primary human fibroblasts. By performing Western blot analysis with purified virions combined with fractionation experiments, we provide evidence that pUL26 is a novel tegument protein of HCMV that is imported during viral infection. Furthermore, we observed transactivation of the HCMV major immediate-early enhancer-promoter by pUL26, whereas several early and late promoters were not affected. Our data suggest that pUL26 is a novel tegument protein of HCMV with a strong transcriptional activation domain that could play an important role during initiation of the viral replicative cycle.
Cowpea Mosaic Virus 32- and 60-Kilodalton Replication Proteins Target and Change the Morphology of Endoplasmic Reticulum Membranes
Authors: Carette Jan E. , van Lent Jan , MacFarlane Stuart A. , Wellink Joan , van Kammen Ab 
Published: July 2002

ABSTRACT

Cowpea mosaic virus (CPMV) replicates in close association with small membranous vesicles that are formed by rearrangements of intracellular membranes. To determine which of the viral proteins are responsible for the rearrangements of membranes and the attachment of the replication complex, we have expressed individual CPMV proteins encoded by RNA1 in cowpea protoplasts by transient expression and in
Nicotiana benthamiana
plants by using the tobacco rattle virus (TRV) expression vector. The 32-kDa protein (32K) and 60K, when expressed individually, accumulate in only low amounts but are found associated with membranes mainly derived from the endoplasmic reticulum (ER). 24K and 110K are freely soluble and accumulate to high levels. With the TRV vector, expression of 32K and 60K results in rearrangement of ER membranes. Besides, expression of 32K and 60K results in necrosis of the inoculated
N. benthamiana
leaves, suggesting that 32K and 60K are cytotoxic proteins. On the other hand, during CPMV infection 32K and 60K accumulate to high levels without causing necrosis.
Molecular Characterization of VP6 Genes of Human Rotavirus Isolates: Correlation of Genogroups with Subgroups and Evidence of Independent Segregation
Authors: Iturriza Gómara Miren , Wong Cecilia , Blome Sandra , Desselberger Ulrich , Gray Jim 
Published: July 2002

ABSTRACT
A reverse transcription-PCR (RT-PCR) was established to amplify a 379-bp cDNA fragment (nucleotides 747 to 1126, coding for amino acids 241 to 367) of the VP6 gene of group A rotaviruses associated with subgroup (SG) specificity. Thirty-eight human rotavirus strains characterized with SG-specific monoclonal antibodies were subjected to VP6-specific RT-PCR, and PCR amplicons were used for sequencing. Nucleic acid sequencing and phylogenetic analysis of the VP6 amplicons revealed two clusters, or genogroups. Two genetic lineages were distinguished within genogroup I, consisting of strains serologically characterized as SG I, and three genetic lineages were distinguished within genogroup II, composed of strains serologically characterized as SG II, SG I + II, and SG non-I, non-II. Subgrouping of rotaviruses by means of serological methods may result in strains not being assigned the correct SG or in a failure of strains to subgroup. Molecular characterization of the SG-defining region of VP6 provided evidence for independent segregation of the rotavirus genes encoding VP4, VP6, and VP7.
Administration of Recombinant Rhesus Interleukin-12 during Acute Simian Immunodeficiency Virus (SIV) Infection Leads to Decreased Viral Loads Associated with Prolonged Survival in SIVmac251-Infected Rhesus Macaques
Authors: Ansari A. A. , Mayne A. E. , Sundstrom J. B. , Bostik P. , Grimm B. , Altman J. D. , Villinger F. 
Published: July 2002

ABSTRACTThe ability of recombinant rhesus interleukin-12 (rMamu-IL-12) administration during acute simian immunodeficiency virus SIVmac251 infection to influence the quality of the antiviral immune responses was assessed in rhesus macaques. Group I (n= 4) was the virus-only control group. Group II and III received a conditioning regimen of rMamu-IL-12 (10 and 20 μg/kg, respectively, subcutaneously [s.c.]) on days −2 and 0. Thereafter, group II received 2 μg of IL-12 per kg and group III received 10 μg/kg s.c. twice a week for 8 weeks. On day 0 all animals were infected with SIVmac251 intravenously. While all four group I animals and three of four group II animals died by 8 and 10 months post infection (p.i.), all four group III animals remained alive for >20 months p.i. The higher IL-12 dose led to lower plasma viral loads and markedly lower peripheral blood mononuclear cell and lymph node proviral DNA loads. During the acute viremia phase, the high-IL-12-dose monkeys showed an increase in CD3−CD8α/α+and CD3+CD8 α/α+cells and, unlike the control and low-IL-12-dose animals, did not demonstrate an increase in CD4+CD45RA+CD62L+naive cells. The high-IL-12-dose animals also demonstrated that both CD8α/α+and CD8α/β+cells produced antiviral factors early p.i., whereas only CD8α/β+cells retained this function late p.i. Long-term survival correlated with sustained high levels of SIVgag/poland SIVenvcytotoxic T lymphocytes and retention of high memory responses against nominal antigens. This is the first study to demonstrate the capacity of IL-12 to significantly protect macaques from SIV-induced disease, and it provides a useful model to more precisely identify correlates of virus-specific disease-protective responses.
Identification of Temperature-Sensitive Mutations in the Phosphoprotein of Respiratory Syncytial Virus That Are Likely Involved in Its Interaction with the Nucleoprotein
Authors: Lu Bin , Brazas Robert , Ma Chien-Hui , Kristoff Tina , Cheng Xing , Jin Hong 
Published: July 2002

ABSTRACT
The phosphoprotein (P) of human respiratory syncytial virus (RSV) is an essential component of the viral RNA polymerase, along with the large polymerase (L), nucleocapsid (N), and M2-1 proteins. By screening a randomly mutagenized P gene cDNA library, two independent mutations, one with a substitution of glycine at position 172 by serine (G172S) and the other with a substitution of glutamic acid at position 176 by glycine (E176G), were identified to result in the loss of N-P interaction at 37°C in the yeast two-hybrid assay. Both P mutants exhibited greatly reduced activity in supporting the replication and transcription of an RSV minigenome replicon at 37 and 39°C. The G172S and E176G mutations were introduced individually into the RSV A2 (rA2) antigenomic cDNA, and recombinant viruses, rA2-P172 and rA2-P176, were obtained. Both viruses replicate as well as wild-type A2 virus in both Vero and HEp-2 cells at 33°C, but each mutant virus exhibited temperature-sensitive replication in both cell lines. rA2-P176 is more temperature sensitive than rA2-P172. Coimmunoprecipitation of the N protein with each P mutant from virus-infected cells demonstrates that N-P interaction is impaired at 37°C. In addition, the levels of replication of rA2-P172 and rA2-P176 in the lungs of mice and cotton rats were reduced. As is the case with the in vitro assays, rA2-P176 is more restricted in replication in the lower respiratory tract of mice and cotton rats than rA2-P172. During in vitro passage at 37°C, the E176G mutation in rA2-P176 was rapidly changed from glycine to predominantly aspartic acid; mutations to cysteine or serine were also detected. All of the revertants lost the temperature-sensitive phenotype. To analyze the importance of the amino acids in the region from positions 161 to 180 for the P protein function, additional mutations were introduced and their functions were analyzed in vitro. A double mutant containing both G172S and E176G changes in the P gene, substitution of the three charged residues at positions 174 to 176 by alanine, and a deletion of residues from positions 161 to 180 completely abolished the P protein function in the minigenome assay. Thus, the amino acids at positions 172 and 176 and the adjacent charged residues play critical roles in the function of the P protein.
Mapping of Genes Involved in Murine Herpes Simplex Virus Keratitis: Identification of Genes and Their Modifiers
Authors: Norose Kazumi , Yano Akihiko , Zhang Xiang-Ming , Blankenhorn Elizabeth , Heber-Katz Ellen 
Published: July 2002

ABSTRACTHerpes simplex keratitis (HSK) is an inflammatory response to viral infection and self antigens in the cornea and is a major cause of blindness. Using two strains of mice which are susceptible (129/SVEV) and resistant (C57BL/6) to herpes simplex virus (HSV) strain KOS, (129/SVEV × C57BL/6)F2mice were generated and examined for their disease susceptibility in terms of clinical symptoms, ocular disease, and antibody production following corneal scarification with HSV (KOS). A genome-wide screen was carried out using microsatellite markers to determine the genetic loci involved in this response. Loci on chromosomes 4, 5, 12, 13, and 14 were shown to be involved in general susceptibility to clinical disease, whereas loci on chromosomes 10 and 17 were shown to be unique to ocular disease.
Altering Expression Levels of Human Immunodeficiency Virus Type 1 gp120-gp41 Affects Efficiency but Not Kinetics of Cell-Cell Fusion
Authors: Lineberger Janet E. , Danzeisen Renee , Hazuda Daria J. , Simon Adam J. , Miller Michael D. 
Published: July 2002

ABSTRACT
Human immunodeficiency virus (HIV) entry into a host cell requires the fusion of virus and cellular membranes that is driven by interaction of the viral envelope glycoproteins gp120 and gp41 (gp120/gp41) with CD4 and a coreceptor, typically either CXCR4 or CCR5. The stoichiometry of gp120/gp41:CD4:CCR5 necessary to initiate membrane fusion is not known. To allow an examination of early events in gp120/gp41-driven membrane fusion, we developed a novel real-time cell-cell fusion assay. Using this assay to study fusion kinetics, we found that altering the cell surface density of gp120/gp41 affected the maximal extent of fusion without dramatically altering fusion kinetics. Collectively, these observations are consistent with the view that gp120/gp41-driven membrane fusion requires the formation of a threshold number of fusion-active intercellular gp120/gp41:CD4:CCR5 complexes. Furthermore, the probability of reaching this threshold is governed, in part, by the surface density of gp120/gp41.
African Swine Fever Virus IAP-Like Protein Induces the Activation of Nuclear Factor Kappa B
Authors: Rodríguez Clara I. , Nogal María L. , Carrascosa Angel L. , Salas María L. , Fresno Manuel , Revilla Yolanda 
Published: July 2002

ABSTRACTAfrican swine fever virus (ASFV) encodes a homologue of the inhibitor of apoptosis (IAP) that promotes cell survival by controlling the activity of caspase-3. Here we show that ASFV IAP is also able to activate the transcription factor NF-κB. Thus, transient transfection of the viral IAP increases the activity of an NF-κB reporter gene in a dose-responsive manner in Jurkat cells. Similarly, stably transfected cells expressing ASFV IAP have elevated basal levels of c-rel, an NF-κB-dependent gene. NF-κB complexes in the nucleus were increased in A224L-expressing cells compared with control cells upon stimulation with phorbol myristate acetate (PMA) plus ionomycin. This resulted in greater NF-κB-dependent promoter activity in ASFV IAP-expressing than in control cells, both in basal conditions and after PMA plus ionophore stimulation. The elevated NF-κB activity seems to be the consequence of higher IκB kinase (IKK) basal activity in these cells. The NF-κB-inducing activity of ASFV IAP was abrogated by an IKK-2 dominant negative mutant and enhanced by expression of tumor necrosis factor receptor-associated factor 2.
The quality of research in sports journals: Table 1
Authors: Bleakley C , MacAuley D 
Published: July 2002

Objective: To examine the evidence base of sports medicine research.Methods: A sample of four major journals that present core research in sport and exercise medicine (British Journal of Sports Medicine,Medicine and Science in Sports and Exercise,Journal of Sports Medicine and Physical Fitness, andPhysical Therapy) was examined using assessment criteria taken from the READER method.Results: Randomised controlled trials comprised 10% or less of all original research articles. Observational/descriptive studies were the most commonly published study design. There was a highly significant difference (p<0.0001) in the contents of the four journals but when they were compared by categorising the better quality methods together (randomised control trial, case-control, and cohort studies), the difference was not significant (p = 0.09).Conclusions: The overall pattern of publication type seems remarkably stable over medical journals, indicating that the quality of sports medicine research is comparable to that in other specialities.