bluuebunny/crossref_metadata_2025_split huggingface dataset:
Members of the AP-1 Family, c-Jun and c-Fos, Functionally Interact with JC Virus Early Regulatory Protein Large T Antigen
Authors: Kim Joanne , Woolridge Stefanie , Biffi Renato , Borghi Elisa , Lassak Adam , Ferrante Pasquale , Amini Shohreh , Khalili Kamel , Safak Mahmut 
Published: April 2003

ABSTRACT
The activating protein 1 (AP-1) family of regulatory proteins is characterized as immediate-early inducible transcription factors which were shown to be activated by a variety of stress-related stimuli and to be involved in numerous biological processes, including cellular and viral gene expression, cell proliferation, differentiation, and tumorigenesis. We have recently demonstrated the involvement of the AP-1 family members c-Jun and c-Fos in transcriptional regulation of the human polyomavirus, JC virus (JCV), genome. Here, we further examined their role in JCV gene regulation and replication through their physical and functional interaction with JCV early regulatory protein large T antigen (T-Ag). Transfection and replication studies indicated that c-Jun and c-Fos can significantly diminish T-Ag-mediated JCV gene transcription and replication. Affinity chromatography and coimmunoprecipitation assays demonstrated that c-Jun and T-Ag physically interact with each other. Results from band shift assays showed that the binding efficiency of c-Jun to the AP-1 site was reduced in the presence of T-Ag. In addition, we have mapped, through the use of a series of deletion mutants, the regions of these proteins which are important for their interaction. While the c-Jun interaction domain of T-Ag is localized to the middle portion of the protein, the T-Ag interacting domain of c-Jun maps to its basic-DNA binding region. Results of transient-transfection assays with various c-Jun mutants and T-Ag expression constructs further confirm the specificity of the functional interaction between c-Jun and T-Ag. Taken together, these data demonstrate that immediate-early inducible transcription factors c-Jun and c-Fos physically and functionally interact with JCV major early regulatory protein large T-Ag and that this interaction modulates JCV transcription and replication in glial cells.
Rapid Tumor Formation of Human T-Cell Leukemia Virus Type 1-Infected Cell Lines in Novel NOD-SCID/γcnullMice: Suppression by an Inhibitor against NF-κB
Authors: Dewan M. Zahidunnabi , Terashima Kazuo , Taruishi Midori , Hasegawa Hideki , Ito Mamoru , Tanaka Yuetsu , Mori Naoki , Sata Tetsutaro , Koyanagi Yoshio , Maeda Michiyuki , Kubuki Yoko , Okayama Akihiko , Fujii Masahiro , Yamamoto Naoki 
Published: April 2003

ABSTRACTWe established a novel experimental model for human T-cell leukemia virus type 1 (HTLV-1)-induced tumor using NOD-SCID/γcnull(NOG) mice. This model is very useful for investigating the mechanism of tumorigenesis and malignant cell growth of adult T-cell leukemia (ATL)/lymphoma, which still remains unclear. Nine HTLV-1-infected cell lines were inoculated subcutaneously in the postauricular region of NOG mice. As early as 2 to 3 weeks after inoculation, seven cell lines produced a visible tumor while two transformed cell lines failed to do so. Five of seven lines produced a progressively growing large tumor with leukemic infiltration of the cells in various organs that eventually killed the animals. Leukemic cell lines formed soft tumors, whereas some transformed cell lines developed into hemorrhagic hard tumors in NOG mice. One of the leukemic cell lines, ED-40515(−), was unable to produce visible tumors in NOD-SCID mice with a common γ-chain after 2 weeks. In vivo NF-κB DNA binding activity of the ED-40515(−) cell line was higher and the NF-κB components were changed compared to cells in vitro. Bay 11-7082, a specific and effective NF-κB inhibitor, prevented tumor growth at the sites of the primary region and leukemic infiltration in various organs of NOG mice. This in vivo model of ATL could provide a novel system for use in clarifying the mechanism of growth of HTLV-1-infected cells as well as for the development of new drugs against ATL.
Caspase Cleavage of the Nonstructural Protein NS1 Mediates Replication of Aleutian Mink Disease Parvovirus
Authors: Best Sonja M. , Shelton Janie F. , Pompey Justine M. , Wolfinbarger James B. , Bloom Marshall E. 
Published: April 2003

ABSTRACT

Virus-induced apoptosis of infected cells can limit both the time and the cellular machinery available for virus replication. Hence, many viruses have evolved strategies to specifically inhibit apoptosis. However, Aleutian mink disease parvovirus (ADV) is the first example of a DNA virus that not only induces apoptosis but also utilizes caspase activity to facilitate virus replication. To determine the function of caspase activity during ADV replication, virus-infected cell lysates or purified ADV proteins were incubated with various purified caspases. Caspases cleaved the major nonstructural protein of ADV (NS1) at two caspase recognition sequences, whereas ADV structural proteins could not be cleaved. Importantly, the NS1 products could be identified in ADV-infected cells but were not present in infected cells pretreated with caspase inhibitors. By mutating putative caspase cleavage sites (D to E), we mapped the two cleavage sites to amino acid residues NS1:227 (INTD↓S) and NS1:285 (DQTD↓S). Replication of ADV containing either of these mutations was reduced 10
3
- to 10
4
-fold compared to that of wild-type virus, and a construct containing both mutations was replication defective. Immunofluorescent studies revealed that cleavage was required for nuclear localization of NS1. The requirement for caspase activity during permissive replication suggests that limitation of caspase activation and apoptosis in vivo may be a novel approach to restricting virus replication.
Inhibition of Human Immunodeficiency Virus Type 1 Env-Mediated Fusion by DC-SIGN
Authors: Nobile Cinzia , Moris Arnaud , Porrot Françoise , Sol-Foulon Nathalie , Schwartz Olivier 
Published: April 2003

ABSTRACTDC-SIGN, a lectin expressed on dendritic cell and macrophage subsets, binds to human immunodeficiency virus Env glycoproteins, allowing capture of viral particles. Captured virions either infect target cells or are efficiently transmitted to lymphocytes. Cellular mechanisms underlying the effects of DC-SIGN remain poorly understood. Here we have analyzed the effects of DC-SIGN on viral entry and on syncytium formation induced by Env glycoproteins. The lectin enhanced susceptibility to viral infection and dramatically increased virion internalization. Captured virions accumulated in the vesicular pathway, and their access to the cytosol was altered. Strikingly, the presence of DC-SIGN on target cells inhibited their ability to form syncytia with Env-expressing cells. However, increasing CD4 surface levels on target cells alleviated this inhibitory effect of DC-SIGN. Moreover, the potency of the viral fusion inhibitor T-20 was not affected in DC-SIGN-expressing cells. Altogether, our results indicate that DC-SIGN exerts subtle and complex effects during early steps of HIV type 1 replication. DC-SIGN facilitates capture and accumulation of viral particles in a vesicular compartment and inhibits viral fusion. Competition between CD4 and DC-SIGN for Env binding likely affects virus access to the cytosol and syncytium formation.
Replication Studies Using Genotype 1a Subgenomic Hepatitis C Virus Replicons
Authors: Gu Baohua , Gates Adam T. , Isken Olaf , Behrens Sven-Erik , Sarisky Robert T. 
Published: April 2003

ABSTRACT
Recently, cell-based replicon systems for hepatitis C virus (HCV), in which the nonstructural proteins stably replicate subgenomic viral RNA in Huh7 cells, were developed. To date, one limitation of using these replicon systems to advance drug discovery is the inability of other genotypic derivatives, beyond those of two distinct strains of genotype 1b (HCV-N and Con1), to stably replicate in Huh7 cells. In this report, we evaluated a series of replicon genotype 1a-1b chimeras, as well as a complete genotype 1a replicon clone. A subgenomic replicon construct containing only type 1a sequences failed to generate stable colonies in Huh7 cells even after repeated attempts. Furthermore, addition of an NS5A adaptive mutation (S2204I) which enhances type 1b replicon efficiency was insufficient to confer replication to the wild-type 1a replicon. This subgenomic replicon was subsequently found to be inefficiently translated in Huh7 cells compared to a type 1b replicon, and the attenuation of translation mapped to the N-terminal region of NS3. Therefore, to ensure efficient translation and thereby support replication of the 1a genome, the coding sequence for first 75 residues from type 1a were replaced with the type 1b (strain Con 1) NS3 coding sequence. Although nonstructural proteins were expressed at lower levels with this replicon than with type 1b and although the amount of viral RNA was also severalfold lower (150 copies of positive-strand RNA per cell), the replicon stably replicated in Huh7 cells. Notwithstanding this difference, the ratio of positive- to negative-strand RNA of 26 was similar to that found with the type 1b replicon. Similar results were found for a 1b replicon expressing the type 1a RNA-dependent RNA polymerase. These 1a hybrid replicons maintained sensitivity to alpha interferon (IFN-α), albeit with an eightfold-higher 50% inhibitory concentration than type 1b replicons. Evidence is provided herein to confirm that this differential response to IFN-α may be attributed directly to the type 1a polymerase.
Manganese-Dependent Polioviruses Caused by Mutations within the Viral Polymerase
Authors: Crotty Shane , Gohara David , Gilligan Devin K. , Karelsky Sveta , Cameron Craig E. , Andino Raul 
Published: April 2003

ABSTRACT

Viral RNA-dependent RNA polymerases exhibit great sequence diversity. Only six core amino acids are conserved across all polymerases of positive-strand RNA viruses of eukaryotes. While exploring the function of one of these completely conserved residues, asparagine 297 in the prototypic poliovirus polymerase 3D
pol
, we identified three viable mutants with noncanonical amino acids at this conserved position. Although asparagine 297 could be replaced by glycine or alanine in these mutants, the viruses exhibited Mn
2+
-dependent RNA replication and viral growth. All known RNA polymerases and replicative polymerases of bacterial, eukaryotic, and viral organisms are thought to be magnesium dependent in vivo, and therefore these mutant polioviruses may represent the first viruses with a requirement for an alternative polymerase cation. These results demonstrate the extreme functional flexibility of viral RNA-dependent RNA polymerases. Furthermore, the finding that strictly conserved residues in the nucleotide binding pocket of the polymerase can be altered in a manner that supports virus production suggests that drugs targeting this region of the enzyme will still be susceptible to the problem of drug-resistant escape mutants.
Protein-Protein Interactions between Hepatitis C Virus Nonstructural Proteins
Authors: Dimitrova Maria , Imbert Isabelle , Kieny Marie Paule , Schuster Catherine 
Published: April 2003

ABSTRACT

Replication of the hepatitis C virus (HCV) genome has been proposed to take place close to the membrane of the endoplasmic reticulum in membrane-associated replicase complexes, as is the case with several other plus-strand RNA viruses, such as poliovirus and flaviviruses. The most obvious benefits of this property are the possibility of coupling functions residing in different polypeptidic chains and the sequestration of viral proteins and nucleic acids in a distinct cytoplasmic compartment with high local concentrations of viral components. Indeed, HCV nonstructural (NS) proteins were clearly colocalized in association with membranes derived from the endoplasmic reticulum. This observation, together with the demonstration of the existence of several physical interactions between HCV NS proteins, supports the idea of assembly of a highly ordered multisubunit protein complex(es) probably involved in the replication of the viral genome. The objective of this study, therefore, was to examine all potential interactions between HCV NS proteins which could result in the formation of a replication complex(es). We identified several interacting viral partners by using a glutathione
S
-transferase pull-down assay, by in vitro and ex vivo coimmunoprecipitation experiments in adenovirus-infected Huh-7 cells allowing the expression of HCV NS proteins, and, finally, by using the yeast two-hybrid system. In addition, by confocal laser scanning microscopy, NS proteins were clearly shown to colocalize when expressed together in Huh-7 cells. We have been able to demonstrate the existence of a complex network of interactions implicating all six NS proteins. Our observations confirm previously described associations and identify several novel homo- and heterodimerizations.
Topology of the Membrane-Associated Hepatitis C Virus Protein NS4B
Authors: Lundin Marika , Monné Magnus , Widell Anders , von Heijne Gunnar , Persson Mats A. A. 
Published: April 2003

ABSTRACT

Hepatitis C virus
(HCV) belongs to the
Hepacivirus
genus in the
Flaviviridae
family. Among the least known viral proteins in this family is the nonstructural protein NS4B, which has been suggested to be a part of the replication complex. Hydrophobicity plots indicate a common profile among the NS4B proteins from different members of the
Flaviviridae
family, suggesting a common function. In order to gain a deeper understanding of the nature of HCV NS4B, we have determined localization and topology of this protein by using recombinant HCV NS4B constructs. The protein localized to the endoplasmic reticulum (ER), but also induced a pattern of cytoplasmic foci positive for markers of the ER. Computer predictions of the membrane topology of NS4B suggested that it has four transmembrane segments. The N and C termini were anticipated to be localized in the cytoplasm, because they are processed by the cytoplasmic NS3 protein. By introducing glycosylation sites at various positions in HCV NS4B, we show that the C terminus is cytoplasmic and the loop around residue 161 is lumenal as predicted. Surprisingly, the N-terminal tail was translocated into the lumen in a considerable fraction of the NS4B molecules, most likely by a posttranslational process. Interestingly, NS4B proteins of the yellow fever and dengue viruses also have their N termini located in the ER lumen due to an N-terminal signal peptide not found in NS4B of HCV. A shared topology achieved in two different ways supports the notion of a common function for NS4B in
Flaviviridae
.
Identification of the Hepatitis C Virus RNA Replication Complex in Huh-7 Cells Harboring Subgenomic Replicons
Authors: Gosert Rainer , Egger Denise , Lohmann Volker , Bartenschlager Ralf , Blum Hubert E. , Bienz Kurt , Moradpour Darius 
Published: April 2003

ABSTRACT
Formation of a membrane-associated replication complex, composed of viral proteins, replicating RNA, and altered cellular membranes, is a characteristic feature of plus-strand RNA viruses. Here, we demonstrate the presence of a specific membrane alteration, designated the membranous web, that contains hepatitis C virus (HCV) nonstructural proteins, as well as viral plus-strand RNA, in Huh-7 cells harboring autonomously replicating subgenomic HCV RNAs. Metabolic labeling with 5-bromouridine 5′-triphosphate in the presence of actinomycin D revealed that the membranous web is the site of viral RNA synthesis and therefore represents the replication complex of HCV.
Inhibition of Protease-Resistant Prion Protein Accumulation In Vitro by Curcumin
Authors: Caughey Byron , Raymond Lynne D. , Raymond Gregory J. , Maxson Laura , Silveira Jay , Baron Gerald S. 
Published: April 2003

ABSTRACTInhibition of the accumulation of protease-resistant prion protein (PrP-res) is a prime strategy in the development of potential transmissible spongiform encephalopathy (TSE) therapeutics. Here we show that curcumin (diferoylmethane), a major component of the spice turmeric, potently inhibits PrP-res accumulation in scrapie agent-infected neuroblastoma cells (50% inhibitory concentration, ∼10 nM) and partially inhibits the cell-free conversion of PrP to PrP-res. In vivo studies showed that dietary administration of curcumin had no significant effect on the onset of scrapie in hamsters. Nonetheless, other studies have shown that curcumin is nontoxic and can penetrate the brain, properties that give curcumin advantages over inhibitors previously identified as potential prophylactic and/or therapeutic anti-TSE compounds.
Role of N Glycosylation of Hepatitis B Virus Envelope Proteins in Morphogenesis and Infectivity of Hepatitis Delta Virus
Authors: Sureau Camille , Fournier-Wirth Chantal , Maurel Patrick 
Published: April 2003

ABSTRACT
Hepatitis delta virus (HDV) particles are coated with the large (L), middle (M), and small (S) hepatitis B virus envelope proteins. In the present study, we constructed glycosylation-defective envelope protein mutants and evaluated their capacity to assist in the maturation of infectious HDV in vitro. We observed that the removal of N-linked carbohydrates on the S, M, and L proteins was tolerated for the assembly of subviral hepatitis B virus (HBV) particles but was partially inhibitory for the formation of HDV virions. However, when assayed on primary cultures of human hepatocytes, virions coated with S, M, and L proteins lacking N-linked glycans were infectious. Furthermore, in the absence of M, HDV particles coated with nonglycosylated S and L proteins retained infectivity. These results indicate that carbohydrates on the HBV envelope proteins are not essential for the in vitro infectivity of HDV.
Psychopharmacological treatments in persons with dual diagnosis of psychiatric disorders and developmental disabilities
Authors: Antochi R , Stavrakaki C , Emery P C 
Published: April 2003

Abstract
People with developmental disabilities are at considerable risk for the development of comorbid psychiatric conditions. Psychopharmacological treatments may have a crucial role in a multidisciplinary and multimodal approach to the management of psychopathology in this population. Psychiatric illnesses that are particularly amenable include mood disorders, anxiety disorders, schizophrenia, and attention deficit hyperactivity disorders (ADHDs) and antidepressants, mood stabilisers, anxiolytics, antipsychotics, and stimulants should be considered, respectively. ADHD may also respond to α2-agonists. Psychotropic agents such as β-antagonists can target aggressive, self injurious, and stereotypical behaviours and opioid antagonists may be helpful in treating self injurious behaviour and stereotypy. Selective serotonin reuptake inhibitors, newer anticonvulsants, and atypical neuroleptics are preferred when treating psychiatric disorders among people with developmental disabilities. This paper will review the major studies of pharmacological treatment of mental illness in individuals with developmental disabilities.
Holocene Earthquake Records from the Cascadia Subduction Zone and Northern San Andreas Fault Based on Precise Dating of Offshore Turbidites
Authors: Goldfinger Chris , Nelson C. Hans , Johnson Joel E. ,   The Shipboard Scientific Party
Published: April 2003

▪ Abstract  We present preliminary evidence for a ∼10,000-year earthquake record from two major fault systems based on sediment cores collected along the continental margins of western North America. New stratigraphic evidence from Cascadia demonstrates that 13 earthquakes ruptured the entire margin from Vancouver Island to at least the California border since the eruption of the Mazama ash 7700 years ago. The 13 events above this prominent stratigraphic marker have an average repeat time of 600 years, and the youngest event ∼300 years ago coincides with the coastal record. We also extend the record of past earthquakes to the base of the Holocene (at least 9800 years ago), during which 18 events correlate along the same region. The sequence of Holocene events in Cascadia appears to contain a repeating pattern of events, a tantalizing first look at what may be the long-term behavior of a major fault system.The northern California margin cores show a cyclic record of turbidite beds that may represent Holocene earthquakes on the northern segment of the San Andreas Fault. Preliminary results are in reasonably good agreement with onshore paleoseismic data that indicate an age for the penultimate event in the mid-1600s at several sites and the most likely age for the third event of ∼AD 1300.
Preconditioning with Short Cycles Improves Ischemic Tolerance in Rat Fast- and Slow-Twitch Skeletal Muscle
Authors: Mattei A. , Sutter P.M. , Marx A. , Stierli P. , Heberer M. , Gürke L. 
Published: April 2003

<i>Aim:</i> The aim of this study was to investigate whether the efficacy of ischemic preconditioning (IP) in rat skeletal muscle depends on the duration of the preconditioning cycles. <i>Methods:</i> Rats were divided into four groups (n = 10 each). The right hindlimb of rats in group A were subjected to 2.5 h of tourniquet ischemia followed by 2 h of reperfusion (I-R). Thereafter, muscular function was analyzed in vitro and high-energy phosphates (HEP) were determined by HPLC. Before I-R, right hindlimbs of rats in groups B–D subjected to IP with three cycles each consisting of 2.5, 5 or 10 min of ischemia followed by reperfusion for the same duration. <i>Results:</i> Postischemic function of the extensor muscle was significantly improved with all three preconditioning protocols. Postischemic function of the soleus muscle was only improved by IP with three cycles of 5 min of ischemia and 5 min of reperfusion. Postischemic HEP tissue levels were not influenced by IP. <i>Conclusion:</i> This study shows for the first time that IP increases ischemic tolerance not only of fast-twitch but also of slow-twitch skeletal muscle. The efficacy of IP seems to be less dependent on the duration of the single preconditioning cycle than on the number of cycles performed. Three cycles each of 2.5, 5 or 10 min ischemia and reperfusion significantly improved postischemic skeletal muscle function. Tissue levels of HEPs, however, were not influenced by IP indicating that preservation of HEPs does not play a major role in the effects of IP on rodent skeletal muscle.