| cellular and humoral immune responses to chimeric egfp-pseudocapsids derived from the mouse polyomavirus after their intranasal administration. | mouse polyomavirus (mpyv) vp1-pseudocapsids carrying enhanced green fluorescent protein (egfp-vlps) were used for intranasal immunization of mice. egfp-vlps induced strong anti-vp1 but not anti-egfp antibody production. in vitro restimulation with antigen-pulsed bone marrow-derived dendritic cells (bmdcs) induced remarkable t-cell proliferative response specific for both vp1 and egfp antigen and il-2 and ifn-gamma production. surprisingly, no specific cytotoxic activities against vp1 and egfp pr ... | 2008 | 18468739 |
| host and viral traits predict zoonotic spillover from mammals. | the majority of human emerging infectious diseases are zoonotic, with viruses that originate in wild mammals of particular concern (for example, hiv, ebola and sars). understanding patterns of viral diversity in wildlife and determinants of successful cross-species transmission, or spillover, are therefore key goals for pandemic surveillance programs. however, few analytical tools exist to identify which host species are likely to harbour the next human virus, or which viruses can cross species ... | 2017 | 28636590 |
| minor capsid proteins of mouse polyomavirus are inducers of apoptosis when produced individually but are only moderate contributors to cell death during the late phase of viral infection. | minor structural proteins of mouse polyomavirus (mpyv) are essential for virus infection. to study their properties and possible contributions to cell death induction, fusion variants of these proteins, created by linking enhanced green fluorescent protein (egfp) to their c- or n-termini, were prepared and tested in the absence of other mpyv gene products, namely the tumor antigens and the major capsid protein, vp1. the minor proteins linked to egfp at their c-terminus (vp2-egfp, vp3-egfp) were ... | 2010 | 20121946 |
| polyomavirus bk neutralizing activity in human immunoglobulin preparations. | polyomavirus bk (bkv) infection can cause nephropathy in the allograft kidney. no well-established drug treatment is available at this time. human intravenous immunoglobulins (ivig) have been used as an empiric therapy without proof of effectiveness. | 2010 | 20568674 |
| polyomavirus middle t antigen induces the transcription of osteopontin, a gene important for the migration of transformed cells. | middle t antigen (mt) is the principal oncoprotein of murine polyomavirus. experiments on the acute immediate effects of mt expression on cellular rna levels showed that expression of osteopontin (opn) was strongly induced by mt expression. osteopontin is a protein known to be associated with cancer. it has a role in tumor progression and invasion. protein analysis confirmed that mt induced the secretion of opn into the extracellular medium. expression of antisense opn rna had no effect on the g ... | 2008 | 18337582 |
| mouse polyomavirus enters early endosomes, requires their acidic ph for productive infection, and meets transferrin cargo in rab11-positive endosomes. | mouse polyomavirus (pyv) virions enter cells by internalization into smooth monopinocytic vesicles, which fuse under the cell membrane with larger endosomes. caveolin-1 was detected on monopinocytic vesicles carrying pyv particles in mouse fibroblasts and epithelial cells (33). here, we show that pyv can be efficiently internalized by jurkat cells, which do not express caveolin-1 and lack caveolae, and that overexpression of a caveolin-1 dominant-negative mutant in mouse epithelial cells does no ... | 2006 | 16611921 |
| induction of polyomavirus-specific cd8(+) t lymphocytes by distinct dendritic cell subpopulations. | dendritic cells are pivotal antigen-presenting cells for generating adaptive t-cell responses. here, we show that dendritic cells belonging to either the myeloid-related or lymphoid-related subset are permissive for infection by mouse polyomavirus and, when loaded with a peptide corresponding to the immunodominant anti-polyomavirus cd8(+) t-cell epitope or infected by polyomavirus, are each capable of driving expansion of primary polyomavirus-specific cd8(+) t-cell responses in vivo. | 2001 | 11119625 |
| studies of mouse polyoma virus infection. 1. procedures for quantitation and detection of virus. | three procedures have been compared for usefulness in titration and detection of polyoma virus: production of cytopathic effect (cpe) in mouse embryo tissue culture, production of hi antibody after inoculation into weanling mice (map test), and production of tumors in suckling hamsters during a 3 to 5 week observation period. the tissue culture and mouse antibody production tests were generally comparable in sensitivity, reproducibility, and time required to obtain results. titration by tumor pr ... | 1959 | 13641563 |
| the hamster polyomavirus--a brief review of recent knowledge. | the hamster polyomavirus (hapv) was first described in 1967 as a virus associated with skin epithelioma of the syrian hamster. the tumors appear spontaneously in a hamster colony bred in berlin-buch (hab). virus particles isolated from skin epitheliomas cause lymphoma and leukemia when injected into newborn hamsters from a distinct colony bred in potsdam, germany (hap). the viral genome has been totally sequenced and the overall genetic organization establishes hapv as a member of the polyomavir ... | 2001 | 11210944 |
| the ionophore monensin inhibits mouse polyomavirus dna replication and destabilizes viral early mrnas. | monensin is a ionophore compound with different biological activities. it raises the intralysosomal ph, it binds the plasma membranes particularly at the level of the cisternal system of the golgi apparatus. it causes imbalance in the intramembrane ion traffic and inhibits export of secretory proteins at membrane level. monensin blocks endocytosis and therefore impedes entry of toxic molecules. the drug also inhibits viral proliferation of rna and dna viruses such as vesicular stomatitis, influe ... | 2000 | 10717385 |
| polyomavirus large- and small-t relieve middle-t-induced cell cycle arrest in normal fibroblasts. | papovavirus tumour antigens have been widely used to study cell growth regulation in cultured cells. we investigated the role of mouse polyomavirus t antigens, small-, middle- and large-t, in stimulating growth-arrested ref52 fibroblasts to enter the s phase. microinjecting cells with cdnas encoding the various t antigens showed: first, that middle-t expression blocked cell cycle stimulation by serum; second, that middle-t-arrested cells were released into the s phase upon coexpression of small- ... | 1999 | 10580053 |
| a suboptimal 5' splice site is a cis-acting determinant of nuclear export of polyomavirus late mrnas. | mouse polyomavirus has been used as a model system to study nucleocytoplasmic transport of mrna. three late mrnas encoding the viral capsid proteins are generated by alternative splicing from common pre-mrna molecules. mrnas encoding the virion protein vp2 (mvp2) harbor an unused 5' splice site, and more than half of them remain fully unspliced yet are able to enter the cytoplasm for translation. examination of the intracellular distribution of late viral mrnas revealed, however, that mvp2 molec ... | 1996 | 8887634 |
| activities of various compounds against murine and primate polyomaviruses. | polyomavirus infections in humans are due to bk virus (bkv) and jc virus (jcv). diseases associated with human polyomaviruses occur mostly in immunocompromised adults, e.g., progressive multifocal leukoencephalopathy (pml), caused by jcv, in aids patients and hemorrhagic cystitis and uretral stenosis, caused by bkv, in transplant recipients. no therapy is available for these diseases, which necessitates the development of chemical entities that are active against polyomaviruses. several antivira ... | 1997 | 9055998 |
| protein kinase b/akt is activated by polyomavirus middle-t antigen via a phosphatidylinositol 3-kinase-dependent mechanism. | the middle tumor antigen (middle-t) of mouse polyomavirus is responsible for the transforming potential of this virus. middle-t has been shown to interact with a variety of cellular proteins known to mediate mitogenic signaling, like phosphatase-2a, src family kinases, phosphatidylinositol 3-kinase (pi 3-kinase), the adapter protein shc, phospholipase cgamma-1 and 14-3-3 family proteins. association with shc and pi 3-kinase, respectively, stimulates two independent signaling pathways that are in ... | 1998 | 9484781 |
| consequences of a subtle sialic acid modification on the murine polyomavirus receptor. | polyomaviruses are small, nonenveloped dna tumor viruses with restricted host ranges. virus binding to cell surface receptors is one determinant of viral tropism. although murine polyomavirus is among the best characterized viruses, little is known about the sialic acid-containing receptor and its interaction with viral particles. by using nonradioactive virus binding assays as recently described for the b-lymphotropic papovavirus, murine polyomavirus particles were found to bind in a saturable ... | 1997 | 9223482 |
| comparison of the human genomic structure of the runt domain-encoding pebp2/cbfalpha gene family. | we cloned the human cdna corresponding to the cdna (pebp2alphab-451) encoding the mouse polyomavirus enhancer-binding protein 2alphab-451, representing a major splice variant from acute myeloid leukemia gene 1 (aml1). genomic dna clones of aml1 were also isolated and the exon/intron structure was determined. furthermore, we determined and compared the genomic structures of three mammalian runt domain-containing genes, pebp2alphaa,aml/pebe2alphab and pebp2alphac. | 1996 | 8654962 |
| interactions among the major and minor coat proteins of polyomavirus. | murine polyomavirus contains two related minor coat proteins, vp2 and vp3, in addition to the major coat protein, vp1. the sequence of vp3 is identical to that of the carboxy-terminal two-thirds of vp2. vp2 may serve a role in uncoating of the virus, and both minor coat proteins may be important for viral assembly. in this study, we show that vp3 and a series of deletion mutants of vp3 can be expressed in escherichia coli as fusion proteins to glutathione s-transferase and partially solubilized ... | 1994 | 8189532 |
| a viable mouse polyomavirus mutant without immortalizing or transforming activities. | the polyomavirus mutant, dl1041, has a 375-base pair deletion. it removes most of the sequences that are unique to rodent polyomaviruses and encodes part of the large and middle t-antigens. the mutant was conditionally viable, although both the immortalizing and transforming functions of the t-antigens produced by this mutant were found to be defective. however, the dl1041 mutant was found to be capable of dna replication in rapidly growing mouse 3t6 cells. in contrast, dl1041 dna synthesis coul ... | 1990 | 2171224 |
| influence of the deprivation of a single amino acid on cellular proliferation and survival in rat 3y1 fibroblasts and their derivatives transformed by a wide variety of agents. | we compared proliferation and survival of various syngeneic transformed cell lines under conditions of depletion of 15 amino acids in dulbecco-eagle's medium. we used a normal fibroblast line 3y1 and 22 transformed sublines of 3y1 which had been induced by one of seven transforming agents--simian virus 40, mouse polyomavirus, adenovirus type 12, e1a gene of adenovirus type 12, cdna of harvey murine sarcoma virus, rous sarcoma virus, or n-methyl-n'-nitro-n-nitrosoguanidine. unlike other untransfo ... | 1988 | 2844831 |
| minimal subenhancer requirements for high-level polyomavirus dna replication: a cell-specific synergy of pea3 and pea1 sites. | the cell-specific regulation of dna replication has important implications for the molecular strategy of cellular gene control. mouse polyomavirus (py) dna replication is examined as a model of cell-specific replication control. using an fm3a-derived mouse cell line which expresses early viral proteins (fop cells), we determined the minimal sequence requirements for viral dna replication. fop cells were observed to have much simpler enhancer requirements than 3t6 and many other cells and did not ... | 1990 | 2167444 |
| identification and characterization of the hamster polyomavirus middle t antigen. | hamster polyomavirus (hapv) is associated with lymphoid and hair follicle tumors in syrian hamsters. the early region of hapv has the potential to encode three polypeptides (which are related to the mouse polyomavirus early proteins) and can transform fibroblasts in vitro. we identified the hapv middle t antigen (hamt) as a 45-kda protein. like its murine counterpart, hamt was associated with serine/threonine phosphatase, phosphatidylinositol-3 kinase, and protein tyrosine kinase activities. how ... | 1991 | 1709702 |
| identification of temperature-sensitive dna- mutants of chinese hamster cells affected in cellular and viral dna synthesis. | we described a strategy which facilitates the identification of cell mutants which are restricted in dna synthesis in a temperature-dependent manner. a collection of over 200 cell mutants temperature-sensitive for growth was isolated in established chinese hamster cell lines (cho and v79) by a variety of selective and nonselective techniques. approximately 10% of these mutants were identified as ts dna- based on differential inhibition of macromolecular synthesis at the restrictive temperature ( ... | 1986 | 3796611 |
| host-specific replication of bk virus dna in mouse cell extracts is independently controlled by dna polymerase alpha-primase and inhibitory activities. | the activation of the human polyomavirus bk causes polyomavirus-associated nephropathy in immunocompromised humans. studies of the virus have been restricted since the virus dna replication is species specific. cell-based and cell-free dna replication systems, including the bk virus (bkv) monopolymerase dna replication system using purified proteins, reproduce the species specificity (28). therefore, the major host proteins comprising this assay, dna polymerase alpha-primase (pol-prim) and repli ... | 2010 | 20392840 |
| blue native protein electrophoresis for studies of mouse polyomavirus morphogenesis and interactions between the major capsid protein vp1 and cellular proteins. | morphogenesis of the mouse polyomavirus virion is a complex and not yet well understood process. nuclear lysates of infected cells and cells transiently producing the major capsid protein (vp1) of the mouse polyomavirus and whole-cell lysates were separated by blue native polyacrylamide gel electrophoresis (bn-page) to characterize the participation of cellular proteins in virion precursor complexes. several vp1-specific complexes were found by immunostaining with the anti-vp1 antibody. some of ... | 2011 | 21893097 |
| murine polyomavirus requires the endoplasmic reticulum protein derlin-2 to initiate infection. | the pathways by which viruses enter cells are diverse, but in all cases, infection necessitates the transfer of the viral genome across a cellular membrane. polyomavirus (py) particles, after binding to glycolipid and glycoprotein receptors at the cell surface, are delivered to the lumen of the endoplasmic reticulum (er). the nature and extent of virus disassembly in the er, how the viral genome is transported to the cytosol and subsequently to the nucleus, and whether any cellular proteins are ... | 2006 | 16912321 |
| molecular characterization and action of usnic acid: a drug that inhibits proliferation of mouse polyomavirus in vitro and whose main target is rna transcription. | usnic acid is a normal component of lichen cells. this natural compound has shown different biological and physiological activities that might have a great relevance in pharmacology and clinics. for instance, usnic acid is known for its antibacterial and antiparasitic action. also, the drug has a potential interest in cancer therapy because of its antimitotic and antiproliferative action. the molecular structure of usnic acid has been validated and further explored in this investigation. many bi ... | 2002 | 12106911 |
| virus receptors and tropism. | polyomaviruses are small, tumorigenic, nonenveloped viruses that infect several different species. interaction of these viruses with cell surface receptors represents the initial step during infection of host cells. this interaction can be a major determinant of viral host and tissue tropism. this chapter reviews what is currently known about the cellular receptors for each of five polyomavirus family members: mouse polyomavirus (pyv), jc virus (jcv), bk virus (bkv), lymphotropic papovavirus (lp ... | 2006 | 16626027 |