scholarly journals Replacement of the Replication Factors of Porcine Circovirus (PCV) Type 2 with Those of PCV Type 1 Greatly Enhances Viral Replication InVitro

2010 ◽  
Vol 84 (17) ◽  
pp. 8986-8989 ◽  
Author(s):  
N. M. Beach ◽  
N. M. Juhan ◽  
L. Cordoba ◽  
X. J. Meng
Keyword(s):  
Virus Replication ◽  
Porcine Circovirus Type ◽  
Porcine Circovirus ◽  
Reading Frame ◽  
Factors Affecting ◽  
Replication Factors ◽  
Important Disease ◽  
Chimeric Viruses

ABSTRACT Porcine circovirus type 1 (PCV1), originally isolated as a contaminant of PK-15 cells, is nonpathogenic, whereas porcine circovirus type 2 (PCV2) causes an economically important disease in pigs. To determine the factors affecting virus replication, we constructed chimeric viruses by swapping open reading frame 1 (ORF1) (rep) or the origin of replication (Ori) between PCV1 and PCV2 and compared the replication efficiencies of the chimeric viruses in PK-15 cells. The results showed that the replication factors of PCV1 and PCV2 are fully exchangeable and, most importantly, that both the Ori and rep of PCV1 enhance the virus replication efficiencies of the chimeric viruses with the PCV2 backbone.

scholarly journals Comparison of porcine circovirus type 2 (PCV2)-associated lesions produced by co-infection between two genotypes of PCV2 and two genotypes of porcine reproductive and respiratory syndrome virus

2014 ◽  
Vol 95 (11) ◽  
pp. 2486-2494 ◽  
Author(s):  
Changhoon Park ◽  
Hwi Won Seo ◽  
Su-Jin Park ◽  
Kiwon Han ◽  
Chanhee Chae
Keyword(s):  
Porcine Circovirus Type ◽  
Porcine Circovirus Type 2 ◽  
Daily Weight Gain ◽  
Porcine Circovirus ◽  
Respiratory Syndrome Virus ◽  
Associated Lesions ◽  
Significant Difference ◽  
Concurrent Infections

The objective of this study was to compare the virulence and pathogenicity of a combination of concurrent infections of two genotypes of porcine circovirus type 2 (PCV2) and two genotypes of porcine reproductive and respiratory syndrome virus (PRRSV) in terms of PCV2 viraemia, and PCV2-associated lesions and antigens in co-infected pigs. Pigs with PCV2a (or 2b)/type 1 (or type 2) PRRSV had significantly (P<0.05) higher mean clinical respiratory scores and lower average daily weight gain compared with pigs with PCV2a (or 2b). Co-infection induced significantly lower levels of anti-PCV2 and anti-PRRSV IgG antibodies than infection with one genotype alone, regardless of the genotype of the two viruses. Pigs with PCV2a (or 2b)/type 2 PRRSV had significantly (P<0.05) higher levels of PCV2 viraemia, more severe PCV2-associated lesions, and more PCV2 DNA within the lesions compared with pigs with PCV2a (or 2b)/type 1 PRRSV. However, there was no significant difference in these parameters in pigs with PCV2a/type 2 PRRSV or PCV2b/type 2 PRRSV. The results of this study demonstrate significant differences in the virulence and pathogenicity of type 1 and type 2 PRRSV but no significant differences in the virulence and pathogenicity of PCV2a and PCV2b with respect to the production of PCV2-associated lesions.

scholarly journals Demonstration of Nicking/Joining Activity at the Origin of DNA Replication Associated with the Rep and Rep′ Proteins of Porcine Circovirus Type 1

2006 ◽  
Vol 80 (13) ◽  
pp. 6225-6234 ◽  
Author(s):  
Tobias Steinfeldt ◽  
Tim Finsterbusch ◽  
Annette Mankertz
Keyword(s):  
Dna Replication ◽  
Virus Replication ◽  
Porcine Circovirus Type ◽  
Porcine Circovirus ◽  
Loop Structure ◽  
Stem Loop ◽  
Single Strand Break ◽  
Stem Loop Structure ◽  
Rep Proteins

ABSTRACT The replication of porcine circovirus type 1 (PCV1) is thought to occur by rolling-circle replication (RCR), whereby the introduction of a single-strand break generates a free 3′-hydroxyl group serving as a primer for subsequent DNA synthesis. The covalently closed, single-stranded genome of PCV1 replicates via a double-stranded replicative intermediate, and the two virus-encoded replication-associated proteins Rep and Rep′ have been demonstrated to be necessary for virus replication. However, although postulated to be involved in RCR-based virus replication, the mechanism of action of Rep and Rep′ is as yet unknown. In this study, the ability of PCV1 Rep and Rep′ to “nick” and “join” strand discontinuities within synthetic oligonucleotides corresponding to the origin of replication of PCV1 was investigated in vitro. Both proteins were demonstrated to be able to cleave the viral strand between nucleotides 7 and 8 within the conserved nonanucleotide motif (5′-TAGTATTAC-3′) located at the apex of a putative stem-loop structure. In addition, the Rep and Rep′ proteins of PCV1 were demonstrated to be capable of joining viral single-stranded DNA fragments, suggesting that these proteins also play roles in the termination of virus DNA replication. This joining activity was demonstrated to be strictly dependent on preceding substrate cleavage and the close proximity of origin fragments accomplished by base pairing in the stem-loop structure. The dual “nicking/joining” activities associated with PCV1 Rep and Rep′ are pivotal events underlying the RCR-based replication of porcine circoviruses in mammalian cells.

scholarly journals Properties of expression of protein capside porcine circovirus type 2 in bacterial cells

2021 ◽  
pp. 48-57
Author(s):  
Anastasia D. Titova ◽  
Kirill V. Kudzin ◽  
Vladimir A. Prokulevich
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Porcine Circovirus Type ◽  
Porcine Circovirus Type 2 ◽  
Porcine Circovirus ◽  
Bacterial Cells ◽  
Reading Frame ◽  
E Coli ◽  
Localization Signal

To improve expression of the porcine circovirus type 2 (PCV2) capsid protein in E. coli cells, the corresponding gene was optimized and two variants of the open reading frame were constructed, which encoded the full-sized and shortened capsid proteins as part of the expression vector. Rare codons were replaced, and in the case of a shortened version of the gene, the region corresponding to the N-terminal domain of the protein was deleted. A comparison was made of the expression level of the studied proteins. It was established that the highest level of expression in bacterial cells is achieved by simultaneously optimizing the codons and removing the initial (N-terminal) 108 base pair (bp) portion of the gene, which contains the nuclear localization signal.

scholarly journals Whole-Genome Analysis of Porcine Circovirus Type 2 in Russia

Pathogens ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1631
Author(s):  
Sergei Raev ◽  
Anton Yuzhakov ◽  
Taras Aliper
Keyword(s):  
Genetic Diversity ◽  
Genome Analysis ◽  
Porcine Circovirus Type ◽  
Porcine Circovirus Type 2 ◽  
Porcine Circovirus ◽  
Economic Losses ◽  
Whole Genome ◽  
Whole Genome Analysis ◽  
Reading Frame

Porcine circovirus type 2 (PCV2) is the causative agent of porcine circovirus-associated diseases (PCVAD) that bring about significant economic losses in the pig industry all over the world. The aim of this study was to investigate the genetic diversity of PCV2 in Russia and characterize the available complete genome sequences. PCV2 DNA was detected at all investigated farms located in different regions of Russia. Whole-genome analysis demonstrated that the majority of PCV2 strains belonged to genotype PCV2d (12 out of 14), while PCV2a and PCV2b were only detected at 2 farms (one at each). Further analysis revealed that all antibody recognition sites in Russian PCV2 strains were different from the corresponding epitopes in a PCV2a vaccine strain, suggesting that PCV2a-based vaccines may only provide limited protection against these strains. PCV2d strains could be grouped into 3 distinct lines which shared 98.7–100% identity within open reading frame 2 (ORF2). It is the first study reporting the genetic diversity of PCV2 strains in Russia. Our data indicated that, similarly to China, Europe, and USA, PCV2a and PCV2b have largely been replaced by PCV2d.

scholarly journals Complete Genome Sequence of Porcine Circovirus Strain YiY-3-2-H5 with a Novel Insertion, Isolated from Hunan Province, China

2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Qian Gong ◽  
Yi Hu ◽  
Yang Zhan ◽  
Dongliang Wang ◽  
Naidong Wang ◽  
...  
Keyword(s):  
Complete Genome ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Porcine Circovirus Type ◽  
Hunan Province ◽  
Porcine Circovirus ◽  
Reading Frame ◽  
Pcv2 Strain ◽  
Open Reading Frame 1

The complete genome of porcine circovirus type 2 (PCV2) strain YiY-3-2-H5 contains a cytidine insertion at position 962 in open reading frame 1. This insertion causes a reading frameshift of the rep gene, and thereafter a premature stop codon is present at the 3′ terminal end of this gene.

scholarly journals Crystal Structure of the Dimerized N Terminus of Porcine Circovirus Type 2 Replicase Protein Reveals a Novel Antiviral Interface

2018 ◽  
Vol 92 (18) ◽  
Author(s):  
Gao Luo ◽  
Xiongfei Zhu ◽  
Yang Lv ◽  
Bomin Lv ◽  
Jin'e Fang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Amino Acid ◽  
Virus Replication ◽  
Hydrophobic Interactions ◽  
Porcine Circovirus Type ◽  
Porcine Circovirus ◽  
Protein Dimerization ◽  
Rep Proteins ◽  
N Terminus

ABSTRACT Two replicase (Rep) proteins, Rep and Rep′, are encoded by porcine circovirus (PCV) ORF1; Rep is a full ORF1 transcript, and Rep′ is a truncated transcript generated by splicing. These two proteins are crucial for the rolling-circle replication (RCR) of PCV. The N-terminal sequences of Rep and Rep′ are identical and interact to form homo- or heterodimers. The three types of dimers perform different functions during replication. A structural examination of the interfacing termini has not been performed. In this study, a crystal structure of dimerized Rep protein N termini was resolved at 2.7 Å. The dimerized protein was maintained by nine intermolecular hydrogen bonds and 15 pairs of hydrophobic interactions. The amino acid residue Ile37 participates in 11 of the hydrophobic interactions, mostly with its side chain. To find the predominant sites for protein dimerization and virus replication, a series of mutant proteins and virus replicons were generated by alanine substitution. Of all the single amino acid substitutions, the mutation at Ile37 showed the greatest effect on protein dimerization and virus replication. A double mutation at Leu35 and Ile37 almost eliminated protein dimerization and had the greatest negative effect on virus replication. These studies demonstrate that Leu35 and Ile37 are the most important residues for protein dimerization and are crucial for virus replication. Our results also show that PCV replication can be decreased by disrupting the dimerization of Rep or Rep′ at the N terminus, suggesting that the structural interface responsible for dimerization offers a promising antiviral target. IMPORTANCE Porcine circovirus type 2 (PCV2) is one of the most economically damaging pathogens affecting the swine industry. Although vaccines have been available for more than 10 years, the virus still remains prevalent. More effective strategies for disease prevention are clearly required. The Rep and Rep′ proteins of the virus have identical N-terminal regions that interact with each other, allowing the formation of homo- or heterodimers. The heterodimer has crucial functions during different stages of viral replication. Here, we resolved the crystal structure of the Rep (Rep′) dimerization domain. The individual residues involved in the intermolecular interaction were visualized in the protein structure, and several interactions were verified by mutant analysis. Our studies show that disrupting the interaction decreases viral replication, thus revealing a new target for the design of antiviral agents.

scholarly journals Antibody Recognition of Porcine Circovirus Type 2 Capsid Protein Epitopes after Vaccination, Infection, and Disease

2011 ◽  
Vol 18 (5) ◽  
pp. 749-757 ◽  
Author(s):  
Benjamin R. Trible ◽  
Maureen Kerrigan ◽  
Nicholas Crossland ◽  
Megan Potter ◽  
Kay Faaberg ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Natural Infection ◽  
Porcine Circovirus Type ◽  
Porcine Circovirus Type 2 ◽  
Porcine Circovirus ◽  
Reading Frame ◽  
Antibody Recognition ◽  
Wasting Syndrome ◽  
Study Support

ABSTRACTOpen reading frame 2 (ORF2) of porcine circovirus type 2 (PCV2) codes for the 233-amino-acid capsid protein (CP). Baculovirus-based vaccines that express only ORF2 are protective against clinical disease following experimental challenge or natural infection. The goal of this study was to identify regions in CP preferentially recognized by sera from experimentally infected and vaccinated pigs and to compare these responses to those of pigs diagnosed with porcine circovirus-associated disease (PCVAD), including porcine multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS). The approach was to react porcine sera with CP polypeptide fragments followed by finer mapping studies using overlapping oligopeptides that covered amino acids 141 to 200. The results showed that vaccinated pigs preferentially recognized only the largest polypeptide fragment, CP(43-233). A subset of experimentally infected pigs and pigs with PDNS showed strong reactivity against a CP oligopeptide, 169-STIDYFQPNNKR-180. Alanine scanning identified Y-173, F-174, Q-175, and K-179 as important for antibody recognition. The results from this study support the notion of PCV2 modulation of immunity, including antibody responses that may represent a precursor for disease. The recognition of CP(169-180) and other polypeptides provides opportunities to devise diagnostic tests for monitoring the immunological effectiveness of vaccination.

Sign in / Sign up

Export Citation Format

Share Document