bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adeno-Associated Virus Rep Protein-Mediated Inhibition of Transcription of the Adenovirus Major Late Promoter In Vitro
Authors: Needham Patrick G. , Casper John M. , Kalman-Maltese Vivian , Verrill Kristin , Dignam John David , Trempe James P. 
Published: June 2006

ABSTRACT
Adeno-associated virus (AAV) is a human parvovirus that normally requires a helper virus such as adenovirus (Ad) for replication. The four AAV replication proteins (Rep78, Rep68, Rep52, and Rep40) are pleiotropic effectors of virus integration, replication, transcription, and virion assembly. These proteins exert effects on Ad gene expression and replication. In transient plasmid transfection assays, Rep proteins inhibit gene expression from a variety of transcription promoters. We have examined Rep protein-mediated inhibition of transcription of the Ad major late transcription promoter (AdMLP) in vitro. Rep78/68 are the strongest transcription suppressors and the purine nucleotide binding site in the Rep proteins, and by implication, the ATPase activity or conformational change induced by nucleotide binding is required for full repression. Rep52 has modest effects, and Rep40 exerts no significant effect on transcription. Rep78/68 and their N-terminal 225-residue domain bind to a 55-bp AdMLP DNA fragment in gel shift assays, suggesting that protein-DNA interactions are required for inhibition. This interaction was confirmed in DNase I protection assays and maps to a region extending from the TATA box to the transcription initiation site. Gel shift, DNase I, and chemical cross-linking assays with TATA box-binding protein (TBP) and Rep68 indicate that both proteins interact with each other and with the promoter at adjacent sites. The demonstration of Rep interaction with TBP and the AdMLP suggests that Rep78/68 alter the preinitiation complex of RNA polymerase II transcription. These observations provide new insight into the mechanism of Rep-mediated inhibition of gene expression.
High Pathogenicity of Wild-Type Measles Virus Infection in CD150 (SLAM) Transgenic Mice
Authors: Sellin Caroline I. , Davoust Nathalie , Guillaume Vanessa , Baas Dominique , Belin Marie-Françoise , Buckland Robin , Wild T. Fabian , Horvat Branka 
Published: June 2006

ABSTRACT
Measles virus (MV) infection causes an acute childhood disease, associated in certain cases with infection of the central nervous system and development of a severe neurological disease. We have generated transgenic mice ubiquitously expressing the human protein SLAM (signaling lymphocytic activation molecule), or CD150, recently identified as an MV receptor. In contrast to all other MV receptor transgenic models described so far, in these mice infection with wild-type MV strains is highly pathogenic. Intranasal infection of SLAM transgenic suckling mice leads to MV spread to different organs and the development of an acute neurological syndrome, characterized by lethargy, seizures, ataxia, weight loss, and death within 3 weeks. In addition, in this model, vaccine and wild-type MV strains can be distinguished by virulence. Furthermore, intracranial MV infection of adult transgenic mice generates a subclinical infection associated with a high titer of MV-specific antibodies in the serum. Finally, to analyze new antimeasles therapeutic approaches, we created a recombinant soluble form of SLAM and demonstrated its important antiviral activity both in vitro and in vivo. Taken together, our results show the high susceptibility of SLAM transgenic mice to MV-induced neurological disease and open new perspectives for the analysis of the implication of SLAM in the neuropathogenicity of other morbilliviruses, which also use this molecule as a receptor. Moreover, this transgenic model, in allowing a simple readout of the efficacy of an antiviral treatment, provides unique experimental means to test novel anti-MV preventive and therapeutic strategies.
Efficient Expression of the Adeno-Associated Virus Type 5 P41 Capsid Gene Promoter in 293 Cells Does Not Require Rep
Authors: Ye Chaoyang , Qiu Jianming , Pintel David J. 
Published: June 2006

ABSTRACT

Efficient expression of the adeno-associated virus type 5 (AAV5) P41 capsid gene promoter required adenovirus E1A and/or E1B; however, in contrast to what was observed for expression of the AAV2 capsid gene promoter (P40), neither adenovirus infection nor the large Rep protein was required. Although both the AAV2 and the AAV5 large Rep proteins efficiently bound the (GAGY)
3
Rep-binding element, the AAV5 large Rep protein transactivated transcription of the inducible AAV2 P40 promoter much less well than AAV2 large Rep. Differences in their activation potentials were mapped to the amino-terminal region of the proteins, and the poorly transactivating AAV5 Rep protein could competitively inhibit AAV2 Rep transactivation.
Structured Treatment Interruptions with Tenofovir Monotherapy for Simian Immunodeficiency Virus-Infected Newborn Macaques
Authors: Van Rompay Koen K. A. , Singh Raman P. , Heneine Walid , Johnson Jeffrey A. , Montefiori David C. , Bischofberger Norbert , Marthas Marta L. 
Published: June 2006

ABSTRACT
We demonstrated previously that prolonged tenofovir treatment of infant macaques, starting early during infection with virulent simian immunodeficiency virus (SIVmac251), can lead to persistently low or undetectable viremia even after the emergence of mutants with reduced in vitro susceptibility to tenofovir as a result of a K65R mutation in reverse transcriptase; this control of viremia was demonstrated to be mediated by the generation of effective antiviral immune responses. To determine whether structured treatment interruptions (STI) can induce similar immunologic control of viremia, eight newborn macaques were infected with highly virulent SIVmac251 and started on a tenofovir STI regimen 5 days later. Treatment was withdrawn permanently at 33 weeks of age. All animals receiving STI fared much better than 22 untreated SIVmac251-infected infant macaques. However, there was a high variability among animals in the viral RNA set point after complete drug withdrawal, and none of the animals was able to achieve long-term immunologic suppression of viremia to persistently low levels. Early immunologic and viral markers in blood (including the detection of the K65R mutation) were not predictive of the viral RNA set point after drug withdrawal. These results, which reflect the complex interactions between drug resistance mutations, viral virulence, and drug- and immune-mediated inhibition of virus replication, highlight the difficulties associated with trying to develop STI regimens with predictable efficacy for clinical practice.
Mycovirus Cryphonectria Hypovirus 1 Elements Cofractionate with
trans
-Golgi Network Membranes of the Fungal Host
Cryphonectria parasitica
Authors: Jacob-Wilk Debora , Turina Massimo , Van Alfen Neal K. 
Published: June 2006

ABSTRACT

The mycovirus cryphonectria hypovirus 1 (CHV1) causes proliferation of vesicles in its host,
Cryphonectria parasitica
, the causal agent of chestnut blight. These vesicles have previously been shown to contain both CHV1 genomic double-stranded RNA (dsRNA) and RNA polymerase activity. To determine the cellular origins of these virus-induced membrane structures, we compared the fractionation of several cellular and viral markers. Results showed that viral dsRNA, helicase, polymerase, and protease p29 copurify with
C. parasitica trans
-Golgi network (TGN) markers, suggesting that the virus utilizes the fungal TGN for replication. We also show that the CHV1 protease p29 associates with vesicle membranes and is resistant to treatments that would release peripheral membrane proteins. Thus, p29 behaves as an integral membrane protein of the vesicular fraction derived from the fungal TGN. Protease p29 was also found to be fully susceptible to proteolytic digestion in the absence of detergent and, thus, is wholly or predominantly on the cytoplasmic face of the vesicles. Fractionation analysis of p29 deletion variants showed that sequences in the C terminal of p29 mediate membrane association. In particular, the C-terminal portion of the protein (Met-135-Gly-248) is sufficient for membrane association and is enough to direct p29 to the TGN vesicles in the absence of other viral elements.
The Signal Peptide of the Ebolavirus Glycoprotein Influences Interaction with the Cellular Lectins DC-SIGN and DC-SIGNR
Authors: Marzi Andrea , Akhavan Armin , Simmons Graham , Gramberg Thomas , Hofmann Heike , Bates Paul , Lingappa Vishwanath R. , Pöhlmann Stefan 
Published: June 2006

ABSTRACT
The C-type lectins DC-SIGN and DC-SIGNR (collectively referred to as DC-SIGN/R) bind to the ebolavirus glycoprotein (EBOV-GP) and augment viral infectivity. DC-SIGN/R strongly enhance infection driven by the GP of EBOV subspecies. Zaire (ZEBOV) but have a much less pronounced effect on infection mediated by the GP of EBOV subspecies. Sudan (SEBOV). For this study, we analyzed the determinants of the differential DC-SIGN/R interactions with ZEBOV- and SEBOV-GP. The efficiency of DC-SIGN engagement by ZEBOV-GP was dependent on the rate of GP incorporation into lentiviral particles, while appreciable virion incorporation of SEBOV-GP did not allow robust DC-SIGN/R usage. Forced incorporation of high-mannose carbohydrates into SEBOV-GP augmented the engagement of DC-SIGN/R to the levels observed with ZEBOV-GP, indicating that appropriate glycosylation of SEBOV-GP is sufficient for efficient DC-SIGN/R usage. However, neither signals for N-linked glycosylation unique to SEBOV- or ZEBOV-GP nor the highly variable and heavily glycosylated mucin-like domain modulated the interaction with DC-SIGN/R. In contrast, analysis of chimeric GPs identified the signal peptide as a determinant of DC-SIGN/R engagement. Thus, ZEBOV- but not SEBOV-GP was shown to harbor high-mannose carbohydrates, and GP modification with these glycans was controlled by the signal peptide. These results suggest that the signal peptide governs EBOV-GP interactions with DC-SIGN/R by modulating the incorporation of high-mannose carbohydrates into EBOV-GP. In summary, we identified the level of GP incorporation into virions and signal peptide-controlled glycosylation of GP as determinants of attachment factor engagement.
Cloning, Expression, and Functional Characterization of the Equine Herpesvirus 1 DNA Polymerase and Its Accessory Subunit
Authors: Loregian Arianna , Case Alessandro , Cancellotti Enrico , Valente Carlo , Marsden Howard S. , Palù Giorgio 
Published: June 2006

ABSTRACT
We report the expression and characterization of the putative catalytic subunit (pORF30) and accessory protein (pORF18) of equine herpesvirus 1 DNA polymerase, which are encoded by open reading frames 30 and 18 and are homologous to herpes simplex virus type 1 UL30 and UL42, respectively. In vitro transcription-translation of open reading frames 30 and 18 generated proteins of 136 and 45 kDa, respectively. In vitro-expressed pORF30 possessed basal DNA polymerase activity that was stimulated by pORF18, as measured by DNA polymerase assays in vitro. Purified baculovirus-expressed pORF30 exhibited DNA polymerase activity similar to that of the in vitro-expressed protein, and baculovirus-expressed pORF18 could stimulate both nucleotide incorporation and long-chain DNA synthesis by pORF30 in a dose- and time-dependent manner. The salt optima for activity of both pORF30 and the holoenzyme were substantially different from those for other herpesvirus DNA polymerases. As demonstrated by yeast two-hybrid assays, pORF30 and pORF18 could physically interact, most likely with a 1:1 stoichiometry. Finally, by mutational analysis of the 1,220-residue pORF30, we demonstrated that the extreme C terminus of pORF30 is important for physical and functional interaction with the accessory protein, as reported for UL30 and other herpesvirus DNA polymerases. In addition, a C-proximal region of pORF30, corresponding to residues 1114 to 1172, is involved in binding to, and stimulation by, pORF18. Taken together, the results indicate that pORF30 and pORF18 are the equine herpesvirus 1 counterparts of herpes simplex virus type 1 UL30 and UL42 and share many, but not all, of their characteristics.
Inhibition of Protein Trafficking by Coxsackievirus B3: Multiple Viral Proteins Target a Single Organelle
Authors: Cornell Christopher T. , Kiosses William B. , Harkins Stephanie , Whitton J. Lindsay 
Published: June 2006

ABSTRACT
Despite replicating to very high titers, coxsackieviruses do not elicit strong CD8 T-cell responses, perhaps because antigen presentation is inhibited by virus-induced disruption of host protein trafficking. Herein, we evaluated the effects of three viral nonstructural proteins (2B, 2BC, and 3A) on intracellular trafficking. All three of these proteins inhibited secretion, to various degrees, and directly associated with the Golgi complex, causing trafficking proteins to accumulate in this compartment. The 3A protein almost completely ablated trafficking and secretion, by moving rapidly to the Golgi, and causing its disruption. Using an alanine-scanning 3A mutant, we show that Golgi targeting and disruption can be uncoupled. Thus, coxsackieviruses rely on the combined effects of several gene products that target a single cellular organelle to successfully block protein secretion during an infection. These findings have implications for viral pathogenesis.
Ep-CAM expression in pancreatic and ampullary carcinomas: frequency and prognostic relevance
Authors: Fong D , Steurer M , Obrist P , Barbieri V , Margreiter R , Amberger A , Laimer K , Gastl G , Tzankov A , Spizzo G 
Published: June 2006

Aims:Pancreatic adenocarcinoma is an aggressive gastrointestinal malignancy with only a few long-term survivors even after radical surgery. Patients with ampullary cancer have a better prognosis but adjuvant therapy needs further improvement. Epithelial cell adhesion molecule (Ep-CAM) is strongly expressed in a variety of epithelial cancers and represents a promising target for immunological tumour therapy. Thus, the aim of this study was to investigate Ep-CAM expression and its potential prognostic impact in pancreatic and ampullary carcinomas.Methods:Ep-CAM expression was investigated retrospectively by immunohistochemistry in paraffin-embedded primary tumour tissue samples from a series of consecutive patients with pancreatic (n = 153) and ampullary cancer (n = 34).Results:Ep-CAM overexpression was observed in 85 of 153 pancreatic cancer specimens (56%) and in 29 of 34 ampullary cancer samples (85%). Overall, Ep-CAM failed to be an independent prognostic marker. However, subgroup analyses showed that Ep-CAM overexpression correlated with shorter overall survival among patients with ampullary cancer and advanced stage pancreatic cancer. In the latter subgroup, survival gradually worsened with increasing Ep-CAM scores. Furthermore, in ampullary cancer, Ep-CAM overexpression was found to correlate with tumour stage.Conclusions:Ep-CAM overexpression was detectable in the majority of cases with pancreatic and ampullary cancer. Therefore, Ep-CAM represents an attractive target for immune-based therapeutic interventions in these tumour entities. However, the prognostic value of Ep-CAM overexpression remains undetermined.
Oncogenic Function of a Novel WD-Domain Protein, STRAP, in Human Carcinogenesis
Authors: Halder Sunil K. , Anumanthan Govindaraj , Maddula Ramakoti , Mann Jason , Chytil Anna , Gonzalez Adriana L. , Washington M. Key , Moses Harold L. , Beauchamp R. Daniel , Datta Pran K. 
Published: June 2006

Abstract
The development and progression of malignancies is a complex multistage process that involves the contribution of a number of genes giving growth advantage to cells when transformed. The role of transforming growth factor-β (TGF-β) in carcinogenesis is complex with tumor-suppressor or prooncogenic activities depending on the cell type and the stage of the disease. We have previously reported the identification of a novel WD-domain protein, STRAP, that associates with both TGF-β receptors and that synergizes with the inhibitory Smad, Smad7, in the negative regulation of TGF-β–induced transcription. Here, we show that STRAP is ubiquitously expressed and is localized in both cytoplasm and nucleus. STRAP is up-regulated in 60% colon and in 78% lung carcinomas. Stable expression of STRAP results in activation of mitogen-activated protein kinase/extracellular signal-regulated kinase pathway and in down-regulation of the cyclin-dependent kinase inhibitor p21Cip1, which results in retinoblastoma protein hyperphosphorylation. In addition, we have observed that Smad2/3 phosphorylation, TGF-β–mediated transcription, and growth inhibition are induced in STRAP-knockout mouse embryonic fibroblasts compared with wild-type cells. Ectopic expression of STRAP in A549 lung adenocarcinoma cell line inhibits TGF-β–induced growth inhibition and enhances anchorage-independent growth of these cells. Moreover, overexpression of STRAP increases tumorigenicity in athymic nude mice. Knockdown of endogenous STRAP by small interfering RNA increases TGF-β signaling, reduces ERK activity, increases p21Cip1 expression, and decreases tumorigenicity. Taken together, these results suggest that up-regulation of STRAP in human cancers may provide growth advantage to tumor cells via TGF-β–dependent and TGF-β–independent mechanisms, thus demonstrating the oncogenic function of STRAP. (Cancer Res 2006; 66(12): 6156-66)
Notch3Gene Amplification in Ovarian Cancer
Authors: Park Joon T. , Li Mei , Nakayama Kentaro , Mao Tsui-Lien , Davidson Ben , Zhang Zhen , Kurman Robert J. , Eberhart Charles G. , Shih Ie-Ming , Wang Tian-Li 
Published: June 2006

AbstractGene amplification is one of the common mechanisms that activate oncogenes. In this study, we used single nucleotide polymorphism array to analyze genome-wide DNA copy number alterations in 31 high-grade ovarian serous carcinomas, the most lethal gynecologic neoplastic disease in women. We identified an amplicon at 19p13.12 in 6 of 31 (19.5%) ovarian high-grade serous carcinomas. This amplification was validated by digital karyotyping, quantitative real-time PCR, and dual-color fluorescence in situ hybridization (FISH) analysis. Comprehensive mRNA expression analysis of all 34 genes within the minimal amplicon identified Notch3 as the gene that showed most significant overexpression in amplified tumors compared with nonamplified tumors. Furthermore, Notch3 DNA copy number is positively correlated with Notch3 protein expression based on parallel immunohistochemistry and FISH studies in 111 high-grade tumors. Inactivation of Notch3 by both γ-secretase inhibitor and Notch3-specific small interfering RNA suppressed cell proliferation and induced apoptosis in the cell lines that overexpressed Notch3 but not in those with minimal amount of Notch3 expression. These results indicate that Notch3 is required for proliferation and survival of Notch3-amplified tumors and inactivation of Notch3 can be a potential therapeutic approach for ovarian carcinomas. (Cancer Res 2006; 66(12): 6312-8)
Mitogen-Activated Protein Kinase Phosphatase 2: A Novel Transcription Target of p53 in Apoptosis
Authors: Shen Wen Hong , Wang Jianli , Wu Jingjing , Zhurkin Victor B. , Yin Yuxin 
Published: June 2006

Abstract
The p53 tumor suppressor plays critical roles in diverse cellular responses such as cell cycle arrest, senescence, and apoptosis through transcriptional control of its target genes. Identification and characterization of new p53 target genes will advance our understanding of how p53 exerts its multiple regulatory functions. In this article, we show that mitogen-activated protein kinase phosphatase 2 (MKP2) is a novel transcription target of p53 in mediating apoptosis. Moreover, we identify a 10-bp perfect palindrome motif (CTGGCGCCAG) in the MKP2 promoter as a new binding site for p53 to activate the MKP2 gene. This GC-rich palindrome is completely different from the consensus p53 binding sequence. Induction of MKP2 is highly responsive to oxidative stress in a p53-dependent manner. Interestingly, the p53-dependent induction of MKP2 is prominent only in the cellular response to stimuli leading to apoptosis but not to cell cycle arrest. In response to oxidative stress, MKP2 is not only required for p53-mediated apoptosis, but ectopic MKP2 expression can also enhance apoptotic responses even independent of p53. These data suggest that p53 regulates distinct genes via different binding mechanisms and that MKP2 is an essential target of p53 in signaling apoptosis. (Cancer Res 2006; 66(12): 6033-9)
Influence of Antibiotic Treatment on Breast Carcinoma Development in Proto-neu Transgenic Mice
Authors: Rossini Anna , Rumio Cristiano , Sfondrini Lucia , Tagliabue Elda , Morelli Daniele , Miceli Rosalba , Mariani Luigi , Palazzo Marco , Ménard Sylvie , Balsari Andrea 
Published: June 2006

Abstract
The effect of prolonged antibiotic treatments on tumor development was evaluated in proto-neu transgenic mice, which spontaneously develop mammary carcinomas. Virgin transgenic mice were treated with metronidazole/ciprofloxacin or gentamicin through the drinking water. The hazard ratio [HR; 95% confidence interval (95% CI)] of breast cancer occurrence in metronidazole/ciprofloxacin-treated mice was more than triple that for controls [3.11 (1.13-8.53); P = 0.028], whereas only a slight increase in HR (95% CI) was observed in gentamicin-treated mice [1.39 (0.56-3.47); P = 0.481]. Tumor growth rate in gentamicin-treated mice was significantly faster than in untreated control mice (P = 0.043). Moreover, mammary glands from mice treated with either antibiotic regimen showed increased lobulization, with more numerous and more developed terminal ductal lobular units than in controls. These results indicate that prolonged exposure to relevant doses of antibiotics affects the mammary glands in this particular model of HER-2/neu transgenic mice; further studies to understand the precise mechanism by which antibiotic treatments influence mammary gland differentiation are critical. (Cancer Res 2006; (12): 6219-24)
Fatty Acid Synthase and Cancer: New Application of an Old Pathway
Authors: Kuhajda Francis P. 
Published: June 2006

Abstract
Fatty acid synthase (FAS), the sole mammalian enzyme capable of de novo fatty acid synthesis, is highly expressed in most human carcinomas. FAS is associated with poor prognosis in breast and prostate cancer, is elaborated into the blood of cancer patients, and its inhibition is selectively cytotoxic to human cancer cells. Thus, FAS and fatty acid metabolism in cancer has become a focus for the potential diagnosis and treatment of cancer. (Cancer Res 2006; 66(12): 5977-80)