title: A conditional lethal mutation in Rana grylio virus ORF 53R resulted in a marked reduction in virion formation.
abstract: Rana grylio virus (RGV) is a pathogenic iridovirus that has resulted in high mortality in cultured frog. Here, a recombinant RGV (i53R-RGV-lacIO) containing the inducible lac repressor/operator system was constructed. i53R-RGV-lacIO was a conditional lethal mutant in which the expression of envelope protein 53R was regulated by IPTG. i53R-RGV-lacIO shared characteristics similar to RGV in the presence of IPTG. However, the expression level of 53R, the ability of plaques formation, and the virus titers were strongly reduced in the absence of IPTG. Electron microscopy showed that the number of progeny virus produced by i53R-RGV-lacIO was remarkably reduced without IPTG. Furthermore, over-expression of 53R in vitro could increase titers of i53R-RGV-lacIO in the absence of IPTG. Therefore, the current data suggested that the lac repressor/operator system could regulate gene expression in the recombinant iridovirus. Our study was thought to be the first report of the system in aquatic virus.
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Li-Bo
authors.initials: LB
authors.lastname: He
authors.forename: Xiao-Chan
authors.initials: XC
authors.lastname: Gao
authors.forename: Fei
authors.initials: F
authors.lastname: Ke
authors.forename: Qi-Ya
authors.initials: QY
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004266:DNA Virus Infections / Q000662:veterinary* / Q000821:virology; D005393:Fish Diseases / Q000821:virology*; D005399:Fishes; D015967:Gene Expression Regulation, Viral; D008969:Molecular Sequence Data; D009154:Mutation; D016366:Open Reading Frames; D017995:Ranavirus / Q000235:genetics* / Q000502:physiology; D014759:Viral Envelope Proteins / Q000235:genetics* / Q000378:metabolism; D014771:Virion / Q000235:genetics* / Q000502:physiology; D014779:Virus Replication
chemical_list: D014759:Viral Envelope Proteins
keywords: Conditional lethal mutant; Envelope protein 53R; Gene expression; Rana grylio virus (RGV); Recombinant iridovirus; lac repressor/operator system