| experimental infection of pregnant sows with porcine enteroviruses. | in a series of experiments, smedi a--porcine enterovirus serotype 8--was given by intrauterine route to pregnant gilts at intervals between gestation days 0 and 30, and smedi c-porcine enterovirus serotype 1--was given to pregnant gilts at intervals between gestation days 30 and 41 to 43. antibodies were detected in fetuses from groups inoculated at gestation days 30 and 41 to 43, whereas virus was isolated from fetuses only from groups inoculated at gestation days 41 to 43. when inoculated dire ... | 1980 | 7406265 |
| research on the presence of porcine enterovirus serotype 1 in north-eastern italy. | the liquid-phase blocking sandwich elisa, already developed for foot-and-mouth disease and swine vesicular disease serology, has been employed in pig sera for the antibody detection against porcine enterovirus serotype 1. elisa-titers correlate positively with virus neutralization and their distribution show a high prevalence among the sampled pigs. the serological findings are confirmed by the isolation of a field strain of porcine enterovirus belonging to the serotype 1. | 1993 | 8342367 |
| sequence analysis of a porcine enterovirus serotype 1 isolate: relationships with other picornaviruses. | the majority of the genomic sequence of a porcine enterovirus serotype 1 (pev-1) isolate was determined. the genome was found to contain a large open reading frame which encoded a leader protein prior to the capsid protein region. this showed no sequence identity to other picornavirus leader regions and the sequence data suggested that it does not possess proteolytic activity. the 2a protease was small and showed considerable sequence identity to the aphthoviruses and to equine rhinovirus seroty ... | 1999 | 10466788 |
| sequence determination and phylogenetic analysis of rna-dependent rna polymerase (rdrp) of the porcine enterovirus 1 (pev-1) talfan strain. | the nucleotide sequence of the region including the rna-dependent rna polymerase (rdrp) of the porcine enterovirus 1 (pev-1) talfan strain was determined. amino acid identities of talfan rdrp with those of other picornaviruses were significantly lower than those seen among the viruses of the same genus of picornaviruses. the phylogenetic analysis of rdrp indicated that picornaviruses were divided into 8 clusters, in which talfan was genetically distinct from other picornaviruses in contrast to t ... | 1999 | 10542031 |
| porcine teschoviruses comprise at least eleven distinct serotypes: molecular and evolutionary aspects. | nucleotide sequencing and phylogenetic analysis of 10 recognized prototype strains of the porcine enterovirus (pev) cytopathic effect (cpe) group i reveals a close relationship of the viral genomes to the previously sequenced strain f65, supporting the concept of a reclassification of this virus group into a new picornavirus genus. also, nucleotide sequences of the polyprotein-encoding genome region or the p1 region of 28 historic strains and recent field isolates were determined. the data sugge ... | 2001 | 11160660 |
| genetic reclassification of porcine enteroviruses. | the genetic diversity of porcine teschoviruses (ptvs; previously named porcine enterovirus 1) and most serotypes of porcine enteroviruses (pevs) was studied. following the determination of the major portion of the genomic sequence of ptv reference strain talfan, the nucleotide and derived amino acid sequences of the rna-dependent rna polymerase (rdrp) region, the capsid vp2 region and the 3' non-translated region (3'-ntr) were compared among ptvs and pevs and with other picornaviruses. the seque ... | 2001 | 11161281 |
| unique characteristics of a picornavirus internal ribosome entry site from the porcine teschovirus-1 talfan. | the teschoviruses constitute a recently defined picornavirus genus. most of the genome sequence of the porcine teschovirus-1 (ptv) talfan and several other strains is known. we now demonstrate that initiation of protein synthesis occurs at nucleotide (nt) 412 on the ptv talfan rna and that nt 1 to 405 contains an internal ribosome entry site (ires) that functions efficiently in vitro and within mammalian cells. in comparison with other picornavirus ires elements, the ptv ires is relatively short ... | 2002 | 12388732 |
| functional analyses of rna structures shared between the internal ribosome entry sites of hepatitis c virus and the picornavirus porcine teschovirus 1 talfan. | the internal ribosome entry site (ires) of porcine teschovirus 1 (ptv-1), a member of the picornaviridae family, is quite distinct from other well-characterized picornavirus ires elements, but it displays functional similarities to the ires from hepatitis c virus (hcv), a member of the flaviviridae family. in particular, a dominant negative mutant form of eif4a does not inhibit the activity of the ptv-1 ires. furthermore, there is a high level (ca. 50%) of identity between the ptv-1 and hcv ires ... | 2006 | 16415004 |
| hepatitis c virus-related internal ribosome entry sites are found in multiple genera of the family picornaviridae. | the internal ribosome entry site (ires) elements from porcine enterovirus 8 and simian virus 2, two members of a proposed new genus within the family picornaviridae, were characterized. these ires elements, in common with the porcine teschovirus 1 ires, were found to be related functionally and structurally to the ires element from hepatitis c virus, a member of the family flaviviridae. partial secondary structure predictions were derived and functional assays demonstrated that these ires elemen ... | 2006 | 16528042 |
| antigenic properties of porcine teschovirus 1 (ptv-1) talfan strain and molecular strategy for serotyping of ptvs. | for reliable diagnosis of porcine teschovirus (ptv) infection we created an rt-pcr-based molecular strategy for serotyping that encompassed the dominant neutralizing antigenic site of ptv, followed by phylogenetic analyses of amplicons. we identified neutralizing antigenic sites of ptv-1 talfan strain through epitope mapping of neutralizing monoclonal antibodies (mabs), using synthetic peptides spanning the capsid proteins. all 11 mabs obtained recognized peptides in the ef loop ("puff") of vp2 ... | 2007 | 17265104 |
| molecular analysis of duck hepatitis virus type 1. | the genome sequence of a duck hepatitis virus type 1 (dhv-1) strain was determined. comparative sequence analysis showed that the genome possesses a typical picornarivus organization and also exhibits several unique features, such as the similarity of internal ribosome entry site to that of porcine teschovirus 1 and hepatitis c virus, the presence of a longest 3' untranslated region and a shorter leader protein in the picornaviridae, the absence of a predicted maturation cleavage of vp0, the ass ... | 2007 | 17300822 |
| isolation and molecular characterization of a porcine teschovirus 1 isolate from china. | porcine teschovirus 1 (ptv-1) (swine/ch/imh/03) was isolated from piglets in a farm in inner mongolia province, p.r. china. it was confirmed by electron microscopy, rt-pcr, and sequencing. comparison of the sequences of the amino acid and nucleotides and phylogenetic analysis of the polyprotein showed that ptv swine/ch/imh/03 strain is ptv-1. the isolated virus has closest relationship with talfan strain, they shared 98.9% and 99.5% homology of amino acids and nucleotides, respectively, in the o ... | 2007 | 17432938 |
| the picornavirus avian encephalomyelitis virus possesses a hepatitis c virus-like internal ribosome entry site element. | avian encephalomyelitis virus (aev) is a picornavirus that causes disease in poultry worldwide, and flocks must be vaccinated for protection. aev is currently classified within the hepatovirus genus, since its proteins are most closely related to those of hepatitis a virus (hav). we now provide evidence that the 494-nucleotide-long 5' untranslated region of the aev genome contains an internal ribosome entry site (ires) element that functions efficiently in vitro and in mammalian cells. unlike th ... | 2008 | 18077729 |
| expression of heterologous genes in oncolytic adenoviruses using picornaviral 2a sequences that trigger ribosome skipping. | insertion of picornaviral 2a sequences into mrnas causes ribosomes to skip formation of a peptide bond at the junction of the 2a and downstream sequences, leading to the production of two proteins from a single open reading frame. adenoviral protein ix is a minor capsid protein that has been used to display foreign peptides on the surface of the capsid. we have used 2a sequences from the foot-and-mouth disease virus (fmdv) and porcine teschovirus 1 (ptv-1) to express protein ix (pix) and green f ... | 2008 | 18198369 |
| monocistronic mrnas containing defective hepatitis c virus-like picornavirus internal ribosome entry site elements in their 5' untranslated regions are efficiently translated in cells by a cap-dependent mechanism. | the initiation of protein synthesis on mrnas within eukaryotic cells is achieved either by a 5' cap-dependent mechanism or through internal initiation directed by an internal ribosome entry site (ires). picornavirus ires elements, located in the 5' untranslated region (5'utr), contain extensive secondary structure and multiple upstream aug codons. these features can be expected to inhibit cap-dependent initiation of translation. however, we have now shown that certain mutant hepatitis c virus-li ... | 2008 | 18567818 |
| divergent picornavirus ires elements. | internal ribosome entry site (ires) elements were first identified about 20 years ago within the 5' untranslated region of picornavirus rnas. they direct a cap-independent mechanism of translation initiation on the viral rna. within the picornavirus family it is now known that there are four classes of ires element which vary in size (450-270 nt), they also have different, complex, secondary structures and distinct requirements for cellular proteins to allow them to function. this review describ ... | 2009 | 18675861 |
| polycistronic lentiviral vector for "hit and run" reprogramming of adult skin fibroblasts to induced pluripotent stem cells. | we report the derivation of induced pluripotent stem (ips) cells from adult skin fibroblasts using a single, polycistronic lentiviral vector encoding the reprogramming factors oct4, sox2, and klf4. porcine teschovirus-1 2a sequences that trigger ribosome skipping were inserted between human cdnas for these factors, and the polycistron was subcloned downstream of the elongation factor 1 alpha promoter in a self-inactivating (sin) lentiviral vector containing a loxp site in the truncated 3' long t ... | 2009 | 19415770 |
| conserved functional domains and a novel tertiary interaction near the pseudoknot drive translational activity of hepatitis c virus and hepatitis c virus-like internal ribosome entry sites. | the translational activity of the hepatitis c virus (hcv) internal ribosome entry site (ires) and other hcv-like ires rnas depends on structured rna elements in domains ii and iii, which serve to recruit the ribosomal 40s subunit, eukaryotic initiation factor (eif) 3 and the ternary eif2/met-trna(i)(met)/gtp complex and subsequently domain ii assists subunit joining. porcine teschovirus-1 talfan (ptv-1) is a member of the picornaviridae family, with a predicted hcv-like secondary structure, but ... | 2009 | 19596815 |
| high cleavage efficiency of a 2a peptide derived from porcine teschovirus-1 in human cell lines, zebrafish and mice. | when expression of more than one gene is required in cells, bicistronic or multicistronic expression vectors have been used. among various strategies employed to construct bicistronic or multicistronic vectors, an internal ribosomal entry site (ires) has been widely used. due to the large size and difference in expression levels between genes before and after ires, however, a new strategy was required to replace ires. a self-cleaving 2a peptide could be a good candidate to replace ires because o ... | 2011 | 21602908 |
| Duck Hepatitis A Virus Possesses a Distinct Type IV Internal Ribosome Entry Site Element of Picornavirus. | Sequence analysis of duck hepatitis virus type 1 (DHV-1) led to its classification as the only member of a new genus, Avihepatovirus, of the family Picornaviridae, and so was renamed duck hepatitis A virus (DHAV). The 5' untranslated region (5' UTR) plays an important role in translation initiation and RNA synthesis of the picornavirus. Here, we provide evidence that the 651-nucleotide (nt)-long 5' UTR of DHAV genome contains an internal ribosome entry site (IRES) element that functions efficien ... | 2012 | 22090106 |
| "self-cleaving" 2a peptide from porcine teschovirus-1 mediates cleavage of dual fluorescent proteins in transgenic eimeria tenella. | the "self-cleaving" 2a sequence of picornavirus, which mediates ribosome-skipping events, enables the generation of two or more separate peptide products from one mrna containing one or more "self-cleaving" 2a sequences. in this study, we introduced a single 2a sequence of porcine teschovirus-1 (p2a) linked to two fluorescent protein genes, the enhanced yellow fluorescent protein (eyfp) gene and the red fluorescent protein (rfp) gene, in a single cassette into transgenic eimeria tenella (eter). ... | 2016 | 27352927 |
| expression of enterovirus 71 virus-like particles in transgenic enoki (flammulina velutipes). | no commercial vaccines are currently available for enterovirus 71 (ev71) infection. oral virus-like particle (vlp) vaccines are regarded as a better choice for prevention from food-borne diseases compared with injected whole virus vaccines. unfortunately, the application of oral vlp vaccines produced from transgenic plants was limited due to the concerns of gene contamination. alternatively, using transgenic mushrooms retains the advantages of transgenic plants and tremendously reduce risks of g ... | 2015 | 25957149 |
| enhancement of heterologous gene expression in flammulina velutipes using polycistronic vectors containing a viral 2a cleavage sequence. | agrobacterium tumefaciens-mediated transformation for edible mushrooms has been previously established. however, the enhancement of heterologous protein production and the expression of multi-target genes remains a challenge. in this study, heterologous protein expression in the enoki mushroom flammulina velutipes was notably enhanced using 2a peptide-mediated cleavage to co-express multiple copies of single gene. the polycistronic expression vectors were constructed by connecting multi copies o ... | 2013 | 23516605 |
| expression of cry1ab and cry2ab by a polycistronic transgene with a self-cleavage peptide in rice. | insect resistance to bacillus thuringiensis (bt) crystal protein is a major threat to the long-term use of transgenic bt crops. gene stacking is a readily deployable strategy to delay the development of insect resistance while it may also broaden insecticidal spectrum. here, we report the creation of transgenic rice expressing discrete cry1ab and cry2ab simultaneously from a single expression cassette using 2a self-cleaving peptides, which are autonomous elements from virus guiding the polycistr ... | 2014 | 25333312 |
| cleavage efficient 2a peptides for high level monoclonal antibody expression in cho cells. | linking the heavy chain (hc) and light chain (lc) genes required for monoclonal antibodies (mab) production on a single cassette using 2a peptides allows control of lc and hc ratio and reduces non-expressing cells. four 2a peptides derived from the foot-and-mouth disease virus (f2a), equine rhinitis a virus (e2a), porcine teschovirus-1 (p2a) and thosea asigna virus (t2a), respectively, were compared for expression of 3 biosimilar igg1 mabs in chinese hamster ovary (cho) cell lines. hc and lc wer ... | 2015 | 25621616 |
| rearrangement of influenza virus spliced segments for the development of live-attenuated vaccines. | influenza viral infections represent a serious public health problem, with influenza virus causing a contagious respiratory disease which is most effectively prevented through vaccination. segments 7 (m) and 8 (ns) of the influenza virus genome encode mrna transcripts that are alternatively spliced to express two different viral proteins. this study describes the generation, using reverse genetics, of three different recombinant influenza a/puerto rico/8/1934 (pr8) h1n1 viruses containing m or n ... | 2016 | 27122587 |
| comparing lamin proteins post-translational relative stability using a 2a peptide-based system reveals elevated resistance of progerin to cellular degradation. | nuclear lamins are the major components of the nuclear lamina at the periphery of the nucleus, supporting the nuclear envelope and participating in many nuclear processes, including dna replication, transcription and chromatin organization. a group of diseases, the laminopathies, is associated with mutations in lamin genes. one of the most striking cases is hutchinson-gilford progeria syndrome (hgps) which is the consequence of a lamin a dominant negative mutant named progerin. due to the abnorm ... | 2016 | 27929926 |
| 2a self-cleaving peptide-based multi-gene expression system in the silkworm bombyx mori. | fundamental and applied studies of silkworms have entered the functional genomics era. here, we report a multi-gene expression system (mges) based on 2a self-cleaving peptide (2a), which regulates the simultaneous expression and cleavage of multiple gene targets in the silk gland of transgenic silkworms. first, a glycine-serine-glycine spacer (gsg) was found to significantly improve the cleavage efficiency of 2a. then, the cleavage efficiency of six types of 2as with gsg was analyzed. the shorte ... | 2015 | 26537835 |
| generation of induced pluripotent stem cells from domestic goats. | the creation of genetically modified goats provides a powerful approach for improving animal health, enhancing production traits, animal pharming, and for ensuring food safety all of which are high-priority goals for animal agriculture. the availability of goat embryonic stem cells (escs) that are characteristically immortal in culture would be of enormous benefit for developing genetically modified animals. as an alternative to long-sought goat escs, we generated induced pluripotent stem cells ... | 2015 | 26118622 |
| generation of a variety of stable influenza a reporter viruses by genetic engineering of the ns gene segment. | influenza a viruses (iav) pose a constant threat to the human population and therefore a better understanding of their fundamental biology and identification of novel therapeutics is of upmost importance. various reporter-encoding iav were generated to achieve these goals, however, one recurring difficulty was the genetic instability especially of larger reporter genes. we employed the viral ns segment coding for the non-structural protein 1 (ns1) and nuclear export protein (nep) for stable expr ... | 2015 | 26068081 |
| replicating reoviruses with a transgene replacing the codons for the head domain of the viral spike. | the capacity to modify the reovirus genome facilitates generation of new therapeutic reoviruses. we describe a method for generating replication-competent reoviruses carrying a heterologous transgene. the strategy is based on the expanded-tropism reovirus mutant jin-3, which can infect cells independent of the reovirus receptor junction-adhesion molecule a (jam-a). jin-3 harbors a mutation in the s1 segment, resulting in a g196r substitution in the tail of the spike protein σ1. the use of the ji ... | 2015 | 25588743 |
| [construction of a general piggybac transposon inducible cell immortalization vector and verification of its basic properties]. | in order to construct generally efficient cell immortalization vector, ptp-htert, we modified the traditional piggybac (pb) transposon using artificial synthesis, pcr and enzyme digestion. the modified vector contained the necessary transposon elements, a pb transposase expression cassette, a co-expression selectable element and a human telomerase reverse transcriptase (htert) expression cassette. the co-expression selectable element had two markers, enhanced green fluorescent protein (egfp) gen ... | 2014 | 25423748 |
| expression of multiple transgenes from a single construct using viral 2a peptides in drosophila. | expression of multiple reporter or effector transgenes in the same cell from a single construct is increasingly necessary in various experimental paradigms. the discovery of short, virus-derived peptide sequences that mediate a ribosome-skipping event enables generation of multiple separate peptide products from one mrna. here we describe methods and vectors to facilitate easy production of polycistronic-like sequences utilizing these 2a peptides tailored for expression in drosophila both in vit ... | 2014 | 24945148 |
| [quantitative comparison of expression for genes linked in bicistronic vectors via ires or 2a-peptide of porcine teschovirus-1 sequence]. | simultaneous expression of multiple target genes is often required in biotechnology. multicistronic vectors coding for several proteins are being actively developed for this purpose. in commercially available vectors different variants ofencephalomyocarditis virus internal ribosome entry site (ires emcv) are used most often. however, many researchers consider that utilization ofself-cleaving 2a peptides sequences within multi- and bicistronic vectors is more promising. in this work, we compared ... | 2014 | 24707727 |