Apoptosis

, Volume 15, Issue 6, pp 653–668

Aquatic birnavirus capsid protein, VP3, induces apoptosis via the Bad-mediated mitochondria pathway in fish and mouse cells

  • Chien-Li Chiu
  • Jen-Leih Wu
  • Guor-Mour Her
  • Yi-Li Chou
  • Jiann-Ruey Hong
Original Paper

DOI: 10.1007/s10495-010-0468-x

Cite this article as:
Chiu, C., Wu, J., Her, G. et al. Apoptosis (2010) 15: 653. doi:10.1007/s10495-010-0468-x
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Abstract

Aquatic birnavirus induces post-apoptotic necrotic cell death via a newly synthesized protein-dependent pathway. However, the involvement of viral genome-encoded protein(s) in this death process remains unknown. In the present study, we demonstrated that the submajor capsid protein, VP3, up-regulates the pro-apoptotic protein, Bad, in fish and mouse cells. Western blot analysis revealed that VP3 was expressed in CHSE-214 cells at 4 h post-infection (pi), indicating an early role during viral replication. We cloned the VP3 gene and tested its function in fish and mouse cells; VP3 overexpression induced apoptotic cell death by TUNEL assay. In addition, it up-regulated Bad gene expression in zebrafish ZLE cells by threefold at 12 h post-transfection (pt) and in mouse NIH3T3 cells by tenfold at 24 h pt. VP3 up-regulation of Bad expression altered mitochondria function, inducing mitochondrial membrane potential (MMP) loss and activating initiator caspase-9 and effector caspase-3. Furthermore, reduced Bad expression (65% reduction), MMP loss (up to 40%), and enhanced cell viability (up to 60%) upon expression of VP3 antisense RNA in CHSE-214 cells at 24 h post-IPNV infection was observed. Finally, overexpression of the anti-apoptotic gene, zfBcl-xL, reduced VP3-induced apoptotic cell death and caspase-3 activation at 24 h in fish cells. Taken together, these results suggest that aquatic birnavirus VP3 induces apoptosis via up-regulation of Bad expression and mitochondrial disruption, which activates a downstream caspase-3-mediated death pathway that is blocked by zfBcl-xL.

Keywords

Infectious pancreatic necrosis virusSubmajor capsid VP3Pro-apoptotic BadMitochondrial membrane potential losszfBcl-xLAntisense RNA

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Chien-Li Chiu
    • 1
  • Jen-Leih Wu
    • 2
  • Guor-Mour Her
    • 3
  • Yi-Li Chou
    • 1
  • Jiann-Ruey Hong
    • 1
  1. 1.Laboratory of Molecular Virology and Biotechnology, Institute of BiotechnologyNational Cheng Kung UniversityTainanTaiwan, ROC
  2. 2.Laboratory of Marine Molecular Biology and Biotechnology, Institute of Cellular and Organismic BiologyAcademia SinicaNankang, TaipeiTaiwan, ROC
  3. 3.Institute of Bioscience and BiotechnologyNational Taiwan Ocean UniversityKeelungTaiwan, ROC