GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • American Society for Microbiology  (4)
  • 1
    Online Resource
    Online Resource
    Identification and Functional Analysis of the Novel ORF4 Protein Encoded by Porcine Circovirus Type 2
    American Society for Microbiology ; 2013
    In:  Journal of Virology Vol. 87, No. 3 ( 2013-02), p. 1420-1429
    Details
    In: Journal of Virology, American Society for Microbiology, Vol. 87, No. 3 ( 2013-02), p. 1420-1429
    Abstract: Porcine circovirus type 2 (PCV2) is the primary causative agent of porcine circovirus-associated diseases in pigs. To date, viral proteins Cap, Rep, Rep′, and ORF3, encoded by the PCV2 genome, have been described. Here, transcription and translation of a novel viral gene within the PCV2 genome (designated ORF4) was determined and functionally analyzed in vitro and in vivo . Northern blot analysis indicated that the RNA transcribed from the ORF4 gene is about 180 bp in length and overlaps ORF3 in the same direction. Site-directed mutagenesis confirmed that the viral ORF4 protein is not essential for virus replication in PK-15 cells and in mice infected with an ORF4-deficient PCV2 (PCV2Δ). PCV2Δ triggered higher activity levels of caspase-3 and -8 than wild-type PCV2 (wPCV2) in PK-15 cells. The antigenic epitopes of two mouse monoclonal antibodies (MAbs) raised against the viral ORF4 protein were mapped to the same 19KSSASPR25 peptide. Expression of ORF4 was confirmed using the specific MAbs in wPCV2-infected PK-15 cells and mice. Mice infected with PCV2Δ had a higher serum viral load (genomic copies) and more severe lymphoid tissue damage in the spleen than those infected with wPCV2. Meanwhile, flow-cytometric analysis indicated that the PCV2Δ infection caused a significant decrease of CD4 + and CD8 + T lymphocytes. Our results demonstrate that ORF4 is a newly discovered viral protein that is not essential for PCV2 replication but plays a role in suppressing caspase activity and regulating CD4 + and CD8 + T lymphocytes during PCV2 infection.
    Type of Medium: Online Resource
    ISSN: 0022-538X , 1098-5514
    URL: Article
    DOI: 10.1128/JVI.01443-12
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2013
    detail.hit.zdb_id: 1495529-5
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Caspase-Dependent Apoptosis Induction via Viral Protein ORF4 of Porcine Circovirus 2 Binding to Mitochondrial Adenine Nucleotide Translocase 3
    American Society for Microbiology ; 2018
    In:  Journal of Virology Vol. 92, No. 10 ( 2018-05-15)
    Details
    In: Journal of Virology, American Society for Microbiology, Vol. 92, No. 10 ( 2018-05-15)
    Abstract: Apoptosis is an essential strategy of host defense responses and is used by viruses to maintain their life cycles. However, the apoptotic signals involved in virus replication are poorly known. In the present study, we report the molecular mechanism of apoptotic induction by the viral protein ORF4, a newly identified viral protein of porcine circovirus type 2 (PCV2). Apoptosis detection revealed not only that the activity of caspase-3 and -9 is increased in PCV2-infected and ORF4-transfected cells but also that cytochrome c release from the mitochondria to the cytosol is upregulated. Subsequently, ORF4 protein colocalization with adenine nucleotide translocase 3 (ANT3) was observed using structured illumination microscopy. Moreover, coimmunoprecipitation and pulldown analyses confirmed that the ORF4 protein interacts directly with mitochondrial ANT3 (mtANT3). Binding domain analysis further confirmed that N-terminal residues 1 to 30 of the ORF4 protein, comprising a mitochondrial targeting signal, are essential for the interaction with ANT3. Knockdown of ANT3 markedly inhibited the apoptotic induction of both ORF4 protein and PCV2, indicating that ANT3 plays an important role in ORF4 protein-induced apoptosis during PCV2 infection. Taken together, these data indicate that the ORF4 protein is a mitochondrial targeting protein that induces apoptosis by interacting with ANT3 through the mitochondrial pathway. IMPORTANCE The porcine circovirus type 2 (PCV2) protein ORF4 is a newly identified viral protein; however, little is known about its functions. Apoptosis is an essential strategy of the host defense response and is used by viruses to maintain their life cycles. In the present study, we report the molecular mechanism of the apoptosis induced by the ORF4 protein. The ORF4 protein contains a mitochondrial targeting signal and is an unstable protein that is degraded by the proteasome-dependent pathway. Viral protein ORF4 triggers caspase-3- and -9-dependent cellular apoptosis in mitochondria by directly binding to ANT3. We conclude that the ORF4 protein is a mitochondrial targeting protein and reveal a mechanism whereby circovirus recruits ANT3 to induce apoptosis.
    Type of Medium: Online Resource
    ISSN: 0022-538X , 1098-5514
    URL: Article
    DOI: 10.1128/JVI.00238-18
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2018
    detail.hit.zdb_id: 1495529-5
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Circovirus Transport Proceeds via Direct Interaction of the Cytoplasmic Dynein IC1 Subunit with the Viral Capsid Protein
    American Society for Microbiology ; 2015
    In:  Journal of Virology Vol. 89, No. 5 ( 2015-03), p. 2777-2791
    Details
    In: Journal of Virology, American Society for Microbiology, Vol. 89, No. 5 ( 2015-03), p. 2777-2791
    Abstract: Microtubule transport of circovirus from the periphery of the cell to the nucleus is essential for viral replication in early infection. How the microtubule is recruited to the viral cargo remains unclear. In this study, we observed that circovirus trafficking is dependent on microtubule polymerization and that incoming circovirus particles colocalize with cytoplasmic dynein and endosomes. However, circovirus binding to dynein was independent of the presence of microtubular α-tubulin and translocation of cytoplasmic dynein into the nucleus. The circovirus capsid (Cap) subunit enhanced microtubular acetylation and directly interacted with intermediate chain 1 (IC1) of dynein. N-terminal residues 42 to 100 of the Cap viral protein were required for efficient binding to the dynein IC1 subunit and for retrograde transport. Knockdown of IC1 decreased virus transport and replication. These results demonstrate that Cap is a direct ligand of the cytoplasmic dynein IC1 subunit and an inducer of microtubule α-tubulin acetylation. Furthermore, Cap recruits the host dynein/microtubule machinery to facilitate transport toward the nucleus by an endosomal mechanism distinct from that used for physiological dynein cargo. IMPORTANCE Incoming viral particles hijack the intracellular trafficking machinery of the host in order to migrate from the cell surface to the replication sites. Better knowledge of the interaction between viruses and virus proteins and the intracellular trafficking machinery may provide new targets for antiviral therapies. Currently, little is known about the molecular mechanisms of circovirus transport. Here, we report that circovirus particles enter early endosomes and utilize the microtubule-associated molecular motor dynein to travel along microtubules. The circovirus capsid subunit enhances microtubular acetylation, and N-terminal residues 42 to 100 directly interact with the dynein IC1 subunit during retrograde transport. These findings highlight a mechanism whereby circoviruses recruit dynein for transport to the nucleus via the dynein/microtubule machinery.
    Type of Medium: Online Resource
    ISSN: 0022-538X , 1098-5514
    URL: Article
    DOI: 10.1128/JVI.03117-14
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2015
    detail.hit.zdb_id: 1495529-5
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Conformational Changes and Nuclear Entry of Porcine Circovirus without Disassembly
    American Society for Microbiology ; 2019
    In:  Journal of Virology Vol. 93, No. 20 ( 2019-10-15)
    Details
    In: Journal of Virology, American Society for Microbiology, Vol. 93, No. 20 ( 2019-10-15)
    Abstract: A relatively stable and flexible capsid is critical to the viral life cycle. However, the capsid dynamics and cytosol trafficking of porcine circovirus type 2 (PCV2) during its infectious cycle are poorly understood. Here, we report the structural stability and conformation flexibility of PCV2 virions by genome labeling and the use of three monoclonal antibodies (MAbs) against the native capsid of PCV2. Genome labeling showed that the infectivity of the PCV2 virion was not affected by conjugation with deoxy-5-ethynylcytidine (EdC). Heat stability experiments indicated that PCV2 capsids started to disassemble at 65°C, causing binding incompetence for all antibodies, and the viral genome was released without capsid disassembly upon heating at 60°C. Antibody binding experiments with PCV2 showed that residues 186 to 192 were concealed in the early endosomes of epithelial PK-15 and monocytic 3D4/31 cells with or without chloroquine treatment and then exposed in PK-15 cytosol and the 3D4/31 nucleus. Viral propagation and localization experiments showed that PCV2 replication and cytosol trafficking were not significantly affected by microtubule depolymerization in monocytic 3D4/31 cells treated with nocodazole. These findings demonstrated that nuclear targeting of viral capsids involved conformational changes, the PCV2 genome was released from the assembled capsid, and the transit of PCV2 particles was independent of microtubules in 3D4/31 cells. IMPORTANCE Circovirus is the smallest virus known to replicate autonomously. Knowledge of viral genome release may provide understanding of viral replication and a method to artificially inactivate viral particles. Currently, little is known about the release model of porcine circovirus type 2 (PCV2). Here, we report the release of the PCV2 genome from assembled capsid and the intracellular trafficking of infectious PCV2 by alterations in the capsid conformation. Knowledge of PCV2 capsid stability and dynamics is essential to understanding its infectious cycle and lays the foundation for discovering powerful targets for therapeutic and prophylactic intervention.
    Type of Medium: Online Resource
    ISSN: 0022-538X , 1098-5514
    URL: Article
    DOI: 10.1128/JVI.00824-19
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2019
    detail.hit.zdb_id: 1495529-5
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...