RGNNV induces mitochondria-mediated cell death via newly synthesized protein dependent pathway in fish cells

• Published in: Fish & shellfish immunology Vol. 29; no. 3; pp. 451 - 463
• Main Authors: Wu, Horng-Cherng, Wu, Jen-Leih, Chu, Heuy-Ling, Su, Yu-Chin, Hong, Jiann-Ruey
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2010
• Subjects: Amino Acid Sequence; Animals; Cell Death; Cell Line; Cloning, Molecular; Fish Diseases - metabolism; Gene Expression Regulation, Viral; Gene Knockdown Techniques; Genome, Viral - genetics; Marine; Mitochondria; Mitochondria - metabolism; Molecular Sequence Data; Necrotic cell death; Nervous necrosis virus; Nodaviridae - physiology; RNA interference; RNA viral genome; RNA Virus Infections - metabolism; RNA Virus Infections - veterinary; RNA, Small Interfering - metabolism; Sequence Alignment; Staphylococcal Protein A - genetics; Staphylococcal Protein A - metabolism; Viral death inducer; Viral Proteins - metabolism; Viral death inducer; Necrotic cell death; Mitochondria; RNA viral genome; RNA interference; Nervous necrosis virus
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2010.05.003

The RNA nervous necrosis virus induces necrotic cell death in fish; however, the molecular mechanism remains unknown. In this study, we demonstrated that beta-nodavirus-induced mitochondria-mediated dependent cell death is through newly synthesized protein dependent pathway in replication cycle. We determined that newly synthesized protein dependent pathway is required for red-spotted grouper nervous necrosis virus (RGNNV)-induced cell death. UV irradiation of the virus effectively blocked viral replication and cell death. Next, RGNNV RNA-dependent RNA polymerase (RdRp or protein A) was cloned and its involvement in RNA genome replication and viral protein synthesis was analyzed. Protein A was initially expressed 48 h post-infection and localized to the cytoplasm. Knockdown of protein A expression completely blocked viral genomic replication and expression of viral protein expression RNA1 small hairpin RNA (shRNA) producing cell lines, which coincided with inhibition of phosphatidylserine exposure, mitochondria-mediated death signaling, and increased cell viability 72 h post-infection. Furthermore, RGNNV-induced mitochondria-mediated caspase-3-independent necrotic cell death is dependent on viral synthesized protein dependent pathway at the middle-late replication stage. Taken together, for instance these results suggested that RGNNV induces cell death may require newly synthesized protein for triggering host mitochondria-mediated cell death. These findings may provide new insights into RNA viral pathogenesis.