title: A tumour necrosis factor receptor-like protein encoded by Singapore grouper iridovirus modulates cell proliferation, apoptosis and viral replication.
abstract: It has been demonstrated that tumour necrosis factor receptor (TNFR) homologues encoded by viruses are usually involved in virus immune evasion by regulating the host immune response or mediating apoptotic cell death. Here, a novel TNFR-like protein encoded by Singapore grouper iridovirus (SGIV VP51) was cloned and characterized. Amino acid analysis showed that VP51 contained three cysteine-rich domains (CRDs) and a transmembrane domain at its C terminus. The expression of VP51 in vitro enhanced cell proliferation, and affected cell cycle progression via altering the G1/S transition. Furthermore, VP51 overexpression improved cell viability during SGIV infection via inhibiting virus-induced apoptosis, evidenced by the reduction of apoptotic bodies and the decrease of caspase-3 activation. In addition, overexpression of VP51 increased viral titre and the expression of viral structural protein gene MCP and cell proliferation promoting gene ICP-18. In contrast, the expression of the viral apoptosis inducing gene, LITAF, was significantly decreased. Although all three CRDs were essential for the action of VP51, CRD2 and CRD3 exerted more crucial roles on virus-induced apoptosis, viral gene transcription and virus production, while CRD1 was more crucial for cell proliferation. Together, SGIV TNFR-like products not only affected cell cycle progression and enhanced cell growth by increasing the expression of the virus encoded cell proliferation gene, but also inhibited virus-induced apoptotic cell death by decreasing the expression of the viral apoptosis inducing gene. Our results provided new insights into understanding the underlying mechanism by which iridovirus regulated the apoptotic pathway to complete its life cycle.
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, PR China.|University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, PR China.
authors.forename: Yepin
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, PR China.
authors.forename: Youhua
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, PR China.
authors.forename: Shina
authors.initials: S
authors.lastname: Wei
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, PR China.|University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, PR China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Li
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, PR China.|University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, PR China.
authors.forename: Lingli
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, PR China.|University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, PR China.
authors.forename: Songwei
authors.initials: S
authors.lastname: Ni
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, PR China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Huang
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, PR China.
authors.forename: Qiwei
authors.initials: Q
authors.lastname: Qin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D002453:Cell Cycle; D049109:Cell Proliferation; D002470:Cell Survival; D004266:DNA Virus Infections / Q000503:physiopathology / Q000662:veterinary* / Q000821:virology; D005393:Fish Diseases / Q000503:physiopathology* / Q000821:virology; D054884:Host-Pathogen Interactions; D008969:Molecular Sequence Data; D010473:Perciformes; D017995:Ranavirus / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D018124:Receptors, Tumor Necrosis Factor; D014764:Viral Proteins