title: Complete genome sequence and transcription profiles of the rock bream iridovirus RBIV-C1.
abstract: The family Iridoviridae consists of 5 genera of double-stranded DNA viruses, including the genus Megalocytivirus, which contains species that are important fish pathogens. In a previous study, we isolated the first rock bream iridovirus from China (RBIV-C1) and identified it as a member of the genus Megalocytivirus. In this report, we determined the complete genomic sequence of RBIV-C1 and examined its in vivo expression profiles. The genome of RBIV-C1 is 112333 bp in length, with a GC content of 55% and a coding density of 92%. RBIV-C1 contains 4584 simple sequence repeats, 89.8% of which are distributed among coding regions. A total of 119 potential open reading frames (ORFs) were identified in RBIV-C1, including the 26 core iridovirus genes; 41 ORFs encode proteins that are predicted to be associated with essential biological functions. RBIV-C1 exhibits the highest degree of sequence conservation and colinear arrangement of genes with orange-spotted grouper iridovirus (OSGIV) and rock bream iridovirus (RBIV). The pairwise nucleotide identities are 99.49% between RBIV-C1 and OSGIV and 98.69% between RBIV-C1 and RBIV. Compared to OSGIV, RBIV-C1 contains 11 insertions, 13 deletions, and 103 single nucleotide mutations. Whole-genome transcription analysis showed that following experimental infection of rock bream with RBIV-C1, all but 1 of the 119 ORFs were expressed at different time points and clustered into 3 hierarchical groups based on their expression patterns. These results provide new insights into the genetic nature and gene expression features of megalocytiviruses.
authors.affiliation: Institute of Oceanology, Chinese Academy of Sciences, Qingdao, People's Republic of China.
authors.forename: Bao-Cun
authors.initials: BC
authors.lastname: Zhang
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Bo-Guang
authors.initials: BG
authors.lastname: Sun
authors.forename: Yong
authors.initials: Y
authors.lastname: Fang
authors.forename: Zhi-Zhong
authors.initials: ZZ
authors.lastname: Xiao
authors.forename: Li
authors.initials: L
authors.lastname: Sun
mesh_terms: D000818:Animals; D015967:Gene Expression Regulation, Viral / Q000502:physiology*; D016679:Genome, Viral; D007497:Iridoviridae / Q000235:genetics*; D009154:Mutation; D059467:Transcriptome