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Crucian carp Carassius auratus herpesvirus (CaHV) was isolated from diseased crucian carp with acute gill hemorrhages and high mortality. The CaHV genome was sequenced and analyzed. The data showed that it consists of 275,348 bp and contains 150 predicted ORFs. The architecture of the CaHV genome differs from those of four cyprinid herpesviruses (CyHV1, CyHV2, SY-C1, CyHV3), with insertions, deletions and the absence of a terminal direct repeat. Phylogenetic analysis of the DNA polymerase sequences of 17 strains of Herpesvirales members, and the concatenated 12 core ORFs from 10 strains of alloherpesviruses showed that CaHV clustered together with members of the genus Cyprinivirus, family Alloherpesviridae. [ABSTRACT FROM AUTHOR]

A new grass carp reovirus strain, tentatively named GCReV-109, was isolated in Hubei, China, and its complete genome sequence was determined. The genome contained 11 double-stranded RNA segments (S1-S11) covering 24,620 base pairs. All of the segments had conserved terminal nucleotides, with GUAA/U at the 5' end and UCAUC at the 3' end. Protein sequence comparison showed that GCReV-109 was most closely related to GCRV-GD108 and shared 96.6-99.5 % protein sequence identity but only shared 16.7-46.1 and 15.1-45.4 % identity with GCRV-873 and HGDRV, respectively. Phylogenetic analysis showed that grass carp reovirus strains in China can be divided into three genotypes. Further analysis revealed homology between the GCRV-109 VP56 and HGDRV VP55 proteins, as well as GCReV-109 NS38, GCRV-873 NS38, and HGDRV VP39. The results of these comparisons also indicated that the homology between viruses was not necessarily linked to their geographical distribution. Our study will help in recognizing and understanding the genome structure and genetic diversity of grass carp reovirus. [ABSTRACT FROM AUTHOR]

Infection with Rana grylio virus (RGV), an iridovirus isolated in China in 1995, resulted in a high mortality rate in frogs. The complete genome sequence of RGV was determined and analyzed. The genomic DNA was 105,791 bp long, with 106 open reading frames (ORFs). Dot plot analysis showed that the gene order of RGV shared colinearity with three completely sequenced ranaviruses. A phylogenetic tree was constructed based on concatenated sequences of iridovirus 26 core-gene-encoded proteins, and the result showed high bootstrap support for RGV being a member of the genus Ranavirus and that iridoviruses of other genera also clustered closely. A microRNA (miRNA) prediction revealed that RGV could encode 18 mature miRNAs, many of which were located near genes associated with virus replication. Thirty-three repeated sequences were found in the RGV genome. These results provide insight into the genetic nature of RGV and are useful for laboratory diagnosis for vertebrate iridoviruses. [ABSTRACT FROM AUTHOR]

The two putative proteins RGV-63R and RGV-91R encoded by Rana grylio virus (RGV) are DNA polymerase and proliferating cell nuclear antigen (PCNA) respectively, and are core proteins of iridoviruses. Here, the interaction between RGV-63R and RGV-91R was detected by a yeast two-hybrid (Y2H) assay and further confirmed by co-immunoprecipitation (co-IP) assays. Subsequently, RGV-63R or RGV-91R were expressed alone or co-expressed in two kinds of aquatic animal cells including amphibian Chinese giant salamander thymus cells (GSTCs) and fish Epithelioma papulosum cyprinid cells (EPCs) to investigate their localizations and effects on RGV genome replication. The results showed that their localizations in the two kinds of cells are consistent. RGV-63R localized in the cytoplasm, while RGV-91R localized in the nucleus. However, when co-expressed, RGV-63R localized in both the cytoplasm and the nucleus, and colocalized with RGV-91R in the nucleus. 91R△NLS represents the RGV-91R deleting nuclear localization signal, which is localized in the cytoplasm and colocalized with RGV-63R in the cytoplasm. qPCR analysis revealed that sole expression and co-expression of the two proteins in the cells of two species significantly promoted RGV genome replication, while varying degrees of viral genome replication levels may be linked to the cell types. This study provides novel molecular evidence for ranavirus cross-species infection and replication. [ABSTRACT FROM AUTHOR]

The freshwater cyanobacterial virus (cyanophage) A-4L, a podovirus, can infect the model cyanobacterium Anabaena sp. strain PCC 7120 resulting in a high burst size and forming concentric plaques on its lawns. The complete genome sequence of A-4L was determined by the combination of high-throughput sequencing, terminal transferase-mediated polymerase chain reaction and restriction mapping. It contains 41,750 bp with 810 bp direct terminal repeats and 38 potential open reading frames. As compared with other cyanobacterial podoviruses in diverse ecosystems, the A-4L has the longest terminal repeat and shares similar genome organizations with freshwater members. Furthermore, phylogenetic analysis based on concatenated sequences of eight core proteins indicated that freshwater cyanobacterial podoviruses were clustered together and distinct from marine counterparts, suggesting a clear divergence in the cyanobacterial podovirus lineage between freshwater and marine ecosystems. Our findings uncover the unique genome structure of A-4L which contains long direct terminal repeats, and create the first model system to address knowledge gaps in understanding cyanobacterial virus–host interactions at the molecular level. [ABSTRACT FROM AUTHOR]

Abstract: Genomic sequence of Scophthalmus maximus rhabdovirus (SMRV) isolated from diseased turbot has been characterized. The complete genome of SMRV comprises 11,492 nucleotides and encodes five typical rhabdovirus genes N, P, M, G and L. In addition, two open reading frames (ORF) are predicted overlapping with P gene, one upstream of P and smaller than P (temporarily called Ps), and another in P gene which may encodes a protein similar to the vesicular stomatitis virus C protein. The C ORF is contained within the P ORF. The five typical proteins share the highest sequence identities (48.9%) with the corresponding proteins of rhabdoviruses in genus Vesiculovirus. Phylogenetic analysis of partial L protein sequence indicates that SMRV is close to genus Vesiculovirus. The first 13 nucleotides at the ends of the SMRV genome are absolutely inverse complementarity. The gene junctions between the five genes show conserved polyadenylation signal (CATGA7) and intergenic dinucleotide (CT) followed by putative transcription initiation sequence A(A/G)(C/G)A(A/G/T), which are different from known rhabdoviruses. The entire Ps ORF was cloned and expressed, and used to generate polyclonal antibody in mice. One obvious band could be detected in SMRV-infected carp leucocyte cells (CLCs) by anti-Ps/C serum via Western blot, and the subcellular localization of Ps-GFP fusion protein exhibited cytoplasm distribution as multiple punctuate or doughnut shaped foci of uneven size. [ABSTRACT FROM AUTHOR]