bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reticuloendotheliosis Virus Sequences within the Genomes of Field Strains of Fowlpox Virus Display Variability
Authors: Singh Pratik , Schnitzlein William M. , Tripathy Deoki N. 
Published: April 2003

ABSTRACT
Nine field strains of fowlpox virus (FPV) isolated during a 24-year span from geographically diverse outbreaks of fowlpox in the United States were screened for the presence of reticuloendotheliosis virus (REV) sequences in their genomes by PCR. Each isolate appeared to be heterogeneous in that either a nearly intact provirus or just a 248- or 508-nucleotide fusion of portions of the integrated REV 5′ and 3′ long terminal repeats (LTRs) was exclusively present at the same genomic site. In contrast, four fowlpox vaccines of FPV origin and three originating from pigeonpox virus were genetically homogeneous in having retained only the 248-bp LTR fusion, whereas two other FPV-based vaccines had only the larger one. These remnants of integrated REV presumably arose during homologous recombination at one of the two regions common to both LTRs or during retroviral excision from the FPV genome. Loss of the provirus appeared to be a natural event because the tripartite population could be detected in a field sample (tracheal lesion). Moreover, the provirus was also readily deleted during propagation of FPV in cultured cells, as evidenced by the detection of truncated LTRs after one passage of a plaque-purified FPV recombinant having a “genetically marked” provirus. However, the deletion mutants did not appear to have a substantial replicative advantage in vitro because even after 55 serial passages the original recombinant FPV was still prevalent. As to the in vivo environment, retention of the REV provirus may confer some benefit to FPV for infection of poultry previously vaccinated against fowlpox.
Role of the Serine-Threonine Kinase PAK-1 in Myxoma Virus Replication
Authors: Johnston J. B. , Barrett John W. , Chang Wen , Chung Che-Sheng , Zeng Wei , Masters Jennefer , Mann Melissa , Wang Fuan , Cao Jingxin , McFadden Grant 
Published: April 2003

ABSTRACT
Subversion or appropriation of cellular signal transduction pathways is a common strategy employed by viruses to promote an environment within infected cells that supports the viral replicative cycle. Using subsets of 3T3 murine fibroblasts previously shown to differ in their ability to support myxoma virus (MV) replication, we investigated the role of host serine-threonine kinases (STKs) as potential mediators of the permissive phenotype. Both permissive and nonpermissive 3T3 cells supported equivalent levels of virion binding, entry, and early virus gene expression, indicating that MV tropism in 3T3 cells was not determined by receptor-mediated entry. In contrast, late virus gene expression and viral DNA replication were selectively compromised in restrictive 3T3 cells. Addition of specific protein kinase inhibitors, many of which shared the ability to influence the activity of the STKs p21-activated kinase 1 (PAK-1) and Raf-1 attenuated MV replication in permissive 3T3 cells. Western blot detection of the phosphorylated forms of PAK-1 (Thr423) and Raf-1 (Ser338) confirmed activation of these kinases in permissive cells after MV infection or gamma interferon treatment, but the activated forms of both kinases were greatly reduced or absent in restrictive 3T3 cells. The biological significance of these activations was demonstrated by using the autoinhibitory domain of PAK-1 (amino acids 83 to 149), expression of which reduced the efficiency of MV infection in permissive 3T3 cells concurrent with a decrease in PAK-1 activation. In comparison, overexpression of a constitutively active PAK-1 (T423E) mutant increased MV replication in restrictive 3T3 cells. These observations suggest that induced signaling via cellular STKs may play important roles in determining the permissiveness of host cells to poxvirus infection.
Differentiation of Varicella-Zoster Virus ORF47 Protein Kinase and IE62 Protein Binding Domains and Their Contributions to Replication in Human Skin Xenografts in the SCID-hu Mouse
Authors: Besser Jaya , Sommer Marvin H. , Zerboni Leigh , Bagowski Christoph P. , Ito Hideki , Moffat Jennifer , Ku Chia-Chi , Arvin Ann M. 
Published: April 2003

ABSTRACT
To investigate the role of the ORF47 protein kinase of varicella-zoster virus (VZV), we constructed VZV recombinants with targeted mutations in conserved motifs of ORF47 and a truncated ORF47 and characterized these mutants for replication, phosphorylation, and protein-protein interactions in vitro and for infectivity in human skin xenografts in the SCID-hu mouse model in vivo. Previous experiments showed that ROka47S, a null mutant that makes no ORF47 protein, did not replicate in skin in vivo (J. F. Moffat, L. Zerboni, M. H. Sommer, T. C. Heineman, J. I. Cohen, H. Kaneshima, and A. M. Arvin, Proc. Natl. Acad. Sci. USA 95:11969-11974, 1998). The construction of VZV recombinants with targeted ORF47 mutations made it possible to assess the effects on VZV infection of human skin xenografts of selectively abolishing ORF47 protein kinase activity. ORF47 mutations that resulted in a C-terminal truncation or disrupted the DYS kinase motif eliminated ORF47 kinase activity and were associated with extensive nuclear retention of ORF47 and IE62 proteins in vitro. Disrupting ORF47 kinase function also resulted in a marked decrease in VZV replication and cutaneous lesion formation in skin xenografts in vivo. However, infectivity in vivo was not blocked completely as long as the capacity of ORF47 protein to bind IE62 protein was preserved, a function that we identified and mapped to the N-terminal domain of ORF47 protein. These experiments indicate that ORF47 kinase activity is of critical importance for VZV infection and cell-cell spread in human skin in vivo but suggest that it is the formation of complexes between ORF47 and IE62 proteins, both VZV tegument components, that constitutes the essential contribution of ORF47 protein to VZV replication in vivo.
Kaposi's Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen Induces Expression of the Helix-Loop-Helix Protein Id-1 in Human Endothelial Cells
Authors: Tang Jun , Gordon Gabriel M. , Müller Maike G. , Dahiya Madhu , Foreman Kimberly E. 
Published: April 2003

ABSTRACTKaposi's sarcoma (KS)-associated herpesvirus (KSHV) (also known as human herpesvirus 8) is a gamma-2 herpesvirus believed to be the etiologic agent responsible for KS. The pathogenesis of this potentially life-threatening neoplasm is complex and unclear, and it is currently unknown how KSHV causes KS. Id (named for inhibitor of DNA binding or inhibitor of differentiation) proteins were identified in 1990 and found to be naturally occurring dominant-negative inhibitors of basic helix-loop-helix transcription factors. Id-1, the most well-studied member of this family, has since been shown to play a key role in several biological systems including cellular differentiation, cell cycle regulation, and tumorigenesis. In this report, we demonstrate that Id-1 is expressed at high levels in KS tumor cells both in vitro and in vivo but is expressed at relatively modest levels in endothelial cells (ECs), the likely precursor of the KS tumor cell. Infection of precursor cells with KSHV may be responsible for this enhanced expression, as KSHV infection induced Id-1 27-fold in ECs under our experimental conditions. Furthermore, we demonstrate that the KSHV-encoded latency-associated nuclear antigen (LANA) protein appears to be involved. Expression of LANA in ECs resulted in Id-1 induction that was almost identical to the induction seen with KSHV-infected ECs. These results demonstrate the expression of Id-1 in KS tumor cells and indicate the KSHV LANA protein may be, at least in part, responsible. This may be an important mechanism by which KSHV allows KS tumor cells to escape normal cell cycle regulation and enhances their proliferation.
The RNA Subunit of Telomerase Is Encoded by Marek's Disease Virus
Authors: Fragnet Laëtitia , Blasco Maria A. , Klapper Wolfram , Rasschaert Denis 
Published: April 2003

ABSTRACT

Marek's disease virus (MDV) is a herpesvirus of chickens that induces T lymphomas and tumors within 4 to 5 weeks of infection. Although the ability of MDV to induce tumors was demonstrated many years ago and although a number of viral oncogenic proteins have been identified, the mechanism by which the MDV is implicated in tumorigenesis is still unknown. We report the identification of a virus-encoded RNA telomerase subunit (vTR) within the genome of MDV. This gene is found in the genomic DNA of the oncogenic MDV strains, whereas it is not carried by the nononcogenic MDV strains. The vTR sequence exhibits 88% sequence identity with the chicken gene (cTR). Our functional analysis suggests that this telomerase RNA can reconstitute telomerase activity in a heterologous system (the knockout murine TR
−/−
cell line) by interacting with the telomerase protein component encoded by the host cell. We have also demonstrated that the vTR promoter region is efficient whatever the species of cell line considered and that vTR is expressed in vivo in peripheral blood leukocytes from chickens infected with the oncogenic MDV-RB1B and the vaccine MDV-Rispens strains. The functionality of the vTR gene and the potential implication of vTR in the oncogenesis induced by MDV is discussed.
The Vaccinia Virus I3L Gene Product Is Localized to a Complex Endoplasmic Reticulum-Associated Structure That Contains the Viral Parental DNA
Authors: Welsch Sonja , Doglio Laura , Schleich Sibylle , Krijnse Locker Jacomine 
Published: April 2003

ABSTRACT
The vaccinia virus (VV) I3L gene product is a single-stranded DNA-binding protein made early in infection that localizes to the cytoplasmic sites of viral DNA replication (S. C. Rochester and P. Traktman, J. Virol. 72:2917-2926, 1998). Surprisingly, when replication was blocked, the protein localized to distinct cytoplasmic spots (A. Domi and G. Beaud, J. Gen. Virol. 81:1231-1235, 2000). Here these I3L-positive spots were characterized in more detail. By using an anti-I3L peptide antibody we confirmed that the protein localized to the cytoplasmic sites of viral DNA replication by both immunofluorescence and electron microscopy (EM). Before replication had started or when replication was inhibited with hydroxyurea or cytosine arabinoside, I3L localized to distinct cytoplasmic punctate structures of homogenous size. We show that these structures are not incoming cores or cytoplasmic sites of VV early mRNA accumulation. Instead, morphological and quantitative data indicate that they are specialized sites where the parental DNA accumulates after its release from incoming viral cores. By EM, these sites appeared as complex, electron-dense structures that were intimately associated with the cellular endoplasmic reticulum (ER). By double labeling of cryosections we show that they contain DNA and a viral early protein, the gene product of E8R. Since E8R is a membrane protein that is able to bind to DNA, the localization of this protein to the I3L puncta suggests that they are composed of membranes. The results are discussed in relation to our previous data showing that the process of viral DNA replication also occurs in close association with the ER.
EBNA2 and Activated Notch Induce Expression of BATF
Authors: Johansen Lisa M. , Deppmann Christopher D. , Erickson Kimberly D. , Coffin William F. , Thornton Tina M. , Humphrey Sean E. , Martin Jennifer M. , Taparowsky Elizabeth J. 
Published: April 2003

ABSTRACT

The immortalization of human B lymphocytes by Epstein-Barr virus (EBV) requires the virus-encoded transactivator EBNA2 and the products of both viral and cellular genes which serve as EBNA2 targets. In this study, we identified
BATF
as a cellular gene that is up-regulated dramatically within 24 h following the infection of established and primary human B cells with EBV. The transactivation of
BATF
is mediated by EBNA2 in a B-cell-specific manner and is duplicated in non-EBV-infected B cells by the expression of mammalian Notch proteins. In contrast to other target genes activated by EBNA2, the
BATF
gene encodes a member of the AP-1 family of transcription factors that functions as a negative regulator of AP-1 activity and as an antagonist of cell growth. A potential role for BATF in promoting EBV latency is supported by studies in which BATF was shown to negatively impact the expression of a
BZLF1
reporter gene and to reduce the frequency of lytic replication in latently infected cells. The identification of
BATF
as a cellular target of EBV provides important new information on how programs of viral and cellular gene expression may be coordinated to promote viral latency and control lytic-cycle entry.
Amphipathic Helix-Dependent Localization of NS5A Mediates Hepatitis C Virus RNA Replication
Authors: Elazar Menashe , Cheong Kwang Ho , Liu Ping , Greenberg Harry B. , Rice Charles M. , Glenn Jeffrey S. 
Published: April 2003

ABSTRACT
We identified an N-terminal amphipathic helix (AH) in one of hepatitis C virus (HCV)’s nonstructural proteins, NS5A. This AH is necessary and sufficient for membrane localization and is conserved across isolates. Genetically disrupting the AH impairs HCV replication. Moreover, an AH peptide-mimic inhibits the membrane association of NS5A in a dose-dependent manner. These results have exciting implications for the HCV life cycle and novel antiviral strategies.
Construction of Varicella-Zoster Virus Recombinants from Parent Oka Cosmids and Demonstration that ORF65 Protein Is Dispensable for Infection of Human Skin and T Cells in the SCID-hu Mouse Model
Authors: Niizuma Takahiro , Zerboni Leigh , Sommer Marvin H. , Ito Hideki , Hinchliffe Stewart , Arvin Ann M. 
Published: April 2003

ABSTRACT
We generated an ORF65 deletion mutant by using a cosmid system constructed from the genome of a low-passage clinical isolate (P-Oka). Using the SCID-hu mouse model, we demonstrated that the ORF65 protein is dispensable for viral replication in skin and T cells, which are critical host cell targets during primary varicella-zoster virus infection.
RNA Interference of Human Papillomavirus Type 18 E6 and E7 Induces Senescence in HeLa Cells
Authors: Hall Allison H. S. , Alexander Kenneth A. 
Published: April 2003

ABSTRACT
The human papillomavirus oncoproteins E6 and E7 promote cell proliferation and contribute to carcinogenesis by interfering with the activities of cellular tumor suppressors. We used a small interfering RNA molecule targeting the E7 region of the bicistronic E6 and E7 mRNA to induce RNA interference, thereby reducing expression of E6 and E7 in HeLa cells. RNA interference of E6 and E7 also inhibited cellular DNA synthesis and induced morphological and biochemical changes characteristic of cellular senescence. These results demonstrate that reducing E6 and E7 expression is sufficient to cause HeLa cells to become senescent.
Green Fluorescent Protein-Tagged Retroviral Envelope Protein for Analysis of Virus-Cell Interactions
Authors: Spitzer Dirk , Dittmar Kurt E. J. , Rohde Manfred , Hauser Hansjörg , Wirth Dagmar 
Published: April 2003

ABSTRACT
Fluorescent retroviral envelope (Env) proteins were developed for direct visualization of viral particles. By fusing the enhanced green fluorescent protein (eGFP) to the N terminus of the amphotropic 4070A envelope protein, extracellular presentation of eGFP was achieved. Viruses incorporated the modified Env protein and efficiently infected cells. We used the GFP-tagged viruses for staining retrovirus receptor-positive cells, thereby circumventing indirect labeling techniques. By generating cells which conditionally expressed the GFP-tagged Env protein, we could confirm an inverse correlation between retroviral Env expression and infectivity (superinfection). eGFP-tagged virus particles are suitable for monitoring the dynamics of virus-cell interactions.
Two Major Histocompatibility Complex Class I-Restricted Epitopes of the Borna Disease Virus p10 Protein Identified by Cytotoxic T Lymphocytes Induced by DNA-Based Immunization
Authors: Hashimoto Yoshio , Chen Horng-Shen , Cunningham Cynthia , Malik Tahir H. , Lai Patrick K. 
Published: April 2003

ABSTRACTBorna disease virus (BDV) infection of Lewis rats is the most studied animal model of Borna disease, an often fatal encephalomyelitis. In this experimental model, BDV-specific CD8+cytotoxic T lymphocytes (CTLs) play a prominent role in the immunopathogenesis of infection by the noncytolytic, persistent BDV. Of the six open reading frames of BDV, CTLs to BDV X (p10) and thel-polymerase have never been studied. In this study, we used plasmid immunization to investigate the CTL response to BDV X and N. Plasmid-based immunization was a potent CTL inducer in Lewis rats. Anti-X CTLs were primed by a single injection of the p10 cDNA. Two codominant p10 epitopes, M1SSDLRLTLL10and T8LLELVRRL16, associated with the RT1.Almajor histocompatibility complex class I molecules of the Lewis rats, were identified. In addition, immunization with a BDV p40-expressing plasmid confirmed the previously reported RT1.Al-restricted A230SYAQMTTY238peptide as the CTL target for BDV N. In contrast to the CTL responses, plasmid vaccination was a poor inducer of an antibody response to p10. Three injections of a recombinant eukaryotic expression plasmid of BDV p10 were needed to generate a weak anti-p10 immunoglobulin M response. However, the antibody response could be optimized by a protein boost after priming with cDNA.
Induction of Broad and Potent Anti-Human Immunodeficiency Virus Immune Responses in Rhesus Macaques by Priming with a DNA Vaccine and Boosting with Protein-Adsorbed Polylactide Coglycolide Microparticles
Authors: Otten Gillis , Schaefer Mary , Greer Catherine , Calderon-Cacia Maria , Coit Doris , Kazzaz Jina , Medina-Selby Angelica , Selby Mark , Singh Manmohan , Ugozzoli Mildred , zur Megede Jan , Barnett Susan W. , O'Hagan Derek , Donnelly John , Ulmer Jeffrey 
Published: April 2003

ABSTRACT
Several vaccine technologies were evaluated for their abilities to induce anti-human immunodeficiency virus Gag immune responses in rhesus macaques. While no vaccine alone was able to induce broad and strong immune responses, these were achieved by priming with Gag DNA and boosting with Gag protein adsorbed to polylactide coglycolide microparticles. This regimen elicited strong antibodies, helper T cells, and cytotoxic T lymphocytes and thus holds promise as an effective vaccination scheme.
TWO NOTES ON GENOME REARRANGEMENT
Authors: OZERY-FLATO MICHAL , SHAMIR RON 
Published: April 2003

A central problem in genome rearrangement is finding a most parsimonious rearrangement scenario using certain rearrangement operations. An important problem of this type is sorting a signed genome by reversals and translocations (SBRT). Hannenhalli and Pevzner presented a duality theorem for SBRT which leads to a polynomial time algorithm for sorting a multi-chromosomal genome using a minimum number of reversals and translocations. However, there is one case for which their theorem and algorithm fail. We describe that case and suggest a correction to the theorem and the polynomial algorithm. The solution of SBRT uses a reduction to the problem of sorting a signed permutation by reversals (SBR). The best extant algorithms for SBR require quadratic time. The common approach to solve SBR is by finding a safe reversal using the overlap graph or the interleaving graph of a permutation. We describe a family of signed permutations which proves a quadratic lower bound on the number of affected vertices in the overlap/interleaving graph during any optimal sorting scenario. This implies, in particular, an Ω(n3) lower bound for Bergeron's algorithm.
Reexamining Martinson's Critique: A Cautionary Note for Evaluators
Authors: Farabee David 
Published: April 2003

In 1974, Robert Martinson, an adjunct assistant professor at the City College of New York, published an article titled “What Works?—Questions and Answers About Prison Reform” (Martinson, 1974). In it, he summarized the results of a 3-year project—Effectiveness of Correctional Treatment (ECT)—which reviewed the effectiveness of 231 offender rehabilitation programs that had been evaluated during the prior 30 years (see also Lipton, Martinson, & Wilks, 1975). Based on his analysis of what was the most extensive offender treatment database that existed at that time, he concluded that “with few and isolated exceptions, the rehabilitative efforts that have been reported so far have had no appreciable effect on recidivism” (p. 25). Martinson's article has since been cited, perhaps naively, as one of the precipitating factors that quashed the treatment-oriented zeitgeist of the 1970s. In truth, Martinson may have provided an invaluable service to the rehabilitation movement by inadvertently giving human form to the undercurrents of skepticism that already existed. Thanks to Martinson, a once fragmented cadre of researchers and clinicians found themselves working in concert to refute what Martinson himself later described as a mischaracterization of his argument. But in these fevered attempts to prove Martinson wrong and, in some cases, vilify him personally, we may have ignored the most important part of his message.
Is There an Association between Life Events, Postnatal Depression and Thyroid Dysfunction in Thyroid Antibody Positive Women?
Authors: Oretti Rossana G. , Harris Brian , Lazarus John H. , Parkes Arthur B. , Crownshaw Tina 
Published: April 2003

Background: Postnatal depression is more common in women positive for thyroid autoantibodies, independent of thyroid hormone dysfunction, but the basis of this association is unclear. Aims: The objective of the work reported here has been to investigate from data obtained from previously published research, a possible association between life events, postnatal depression and the development of thyroid dysfunction in women who are positive for thyroid autoantibodies. Method: A cohort of pregnant women whose thyroid antibody status was positive ( N = 115), was identified at antenatal booking (approximately 16 weeks). These, and a group of women negative for thyroid antibodies ( N = 123), were assessed for depression at six to eight weeks postpartum and then at 12, 20 and 28 weeks postpartum according to Research Diagnostic Criteria (RDC). The number and type of life events over the preceding year were also assessed at eight weeks postpartum using Paykel's Life Event Schedule. At four weekly intervals postpartum until six months, thyroid antibody levels and thyroid function (plasma T3 T4 and TSH) were measured. Results: As anticipated, the thyroid antibody status remained the same throughout the study, and there was no difference in the number or type of life events reported in the preceding year, between antibody positive and antibody negative women. Postnatal depression was associated with an excess of both total and negative life events, independent of thyroid antibody status or actual thyroid hormonal status. Women who developed thyroid dysfunction did not report an excess of life events (total, negative or neutral) in the preceding year. Conclusion: There was an excess of reported total and negative life events in women with postnatal depression, but this was independent of thyroid antibody status or function.