Characterization of Singapore grouper iridovirus (SGIV) ORF086R, a putative homolog of ICP18 involved in cell growth control and virus replication
- 313 Downloads
Singapore grouper iridovirus (SGIV), as a causative agent of serious systemic disease, causes significant economic losses in grouper aquaculture. In this study, a novel ICP18 homolog encoded by SGIV ORF086R was identified and characterized. Strikingly, ICP18 homologs can be found in all ranaviruses, but not in other sequenced large DNA viruses. SGIV ICP18 is an immediate-early gene and begins to be transcribed as early as 2 h post-infection (p.i.). Western blotting indicated that SGIV ICP18 is translated as early as 6 h p.i. and is a viral non-envelope protein. Subcellular localization analysis revealed that the SGIV ICP18 displays a finely punctate cytoplasmic pattern. Furthermore, overexpression of SGIV ICP18 can promote the growth of grouper embryonic cells (GP) and contribute to SGIV replication. These results should offer important insights into the pathogenesis of ranaviruses.
KeywordsCell Growth Control ICP18 Protein Punctate Fluorescence ICP18 Gene Ambystoma Tigrinum Virus
This work was supported by grants from the National Basic Research Program of China (973) (2006CB101802), the National High Technology Development Program of China (863) (2006AA09Z445, 2006AA09Z411), National Natural Science Foundation of China (30700616, 30725027) and Chinese Academy of Sciences (KZCX2-YW-BR-08). We thank Professor Zaohe Wu and Jichang Jian, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, for providing facilities to perform the work of gene cloning, plasmid construction and antibody preparation.
- 6.Chinchar VG, Essbauer S, He JG, Hyatt A, Miyazaki T, Seligy D, Williams T (2005) In: Fauqet CM, Mayo MA, Maniloff J, Desselberger U, Ball LA (eds) Iridovirade. Virus taxonomy, VIIIth report of the international committee on taxonomy of viruses. Academic Press, London, pp 163–175Google Scholar
- 20.Reed LJ, Muench H (1938) A simple method of estimating fifty per cent endpoints. Am J Epidemiol 27:493–497Google Scholar
- 21.Sample R, Bryan L, Long S, Majji S, Hoskins G, Sinning A, Olivier J, Chinchar VG (2007) Inhibition of iridovirus protein synthesis and virus replication by antisense morpholino oligonucleotides targeted to the major capsid protein, the 18 kDa immediate-early protein, and a viral homolog of RNA polymerase II. Virology 358:311–320PubMedCrossRefGoogle Scholar
- 25.Teng Y, Hou ZW, Gong J, Liu H, Xie X, Zhang L, Chen XH, Qin QW (2008) Whole-genome transcriptional pro.les of a novel marine fish iridovirus, Singapore grouper iridovirus (SGIV) in virus-infected grouper spleen cell cultures and in orange-spotted grouper, Epinephulus coioides. Virology 377:39–48PubMedCrossRefGoogle Scholar
- 32.Williams T (1996) The iridoviruses. Adv Virus Res 46:347–412Google Scholar
- 34.Willis D, Foglesong D, Granoff A (1984) Nucleotide sequence of an immediate-early frog virus 3 gene. J Virol 53:905–912Google Scholar