Genomic sequence of a ranavirus (family Iridoviridae) associated with salamander mortalities in North America

James K. Jancovich, Jinghe Mao, V. Gregory Chinchar, Christopher Wyatt, Steven T. Case, Sudhir Kumar, Graziela Valente, Sankar Subramanian, Elizabeth W. Davidson, James Collins, Bertram Jacobs

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Abstract

Disease is among the suspected causes of amphibian population declines, and an iridovirus and a chytrid fungus are the primary pathogens associated with amphibian mortalities. Ambystoma tigrinum virus (ATV) and a closely related strain, Regina ranavirus (RRV), are implicated in salamander die-offs in Arizona and Canada, respectively. We report the complete sequence of the ATV genome and partial sequence of the RRV genome. Sequence analysis of the ATV/RRV genomes showed marked similarity to other ranaviruses, including tiger frog virus (TFV) and frog virus 3 (FV3), the type virus of the genus Ranavirus (family Iridoviridae), as well as more distant relationships to lymphocystis disease virus, Chilo iridescent virus, and infectious spleen and kidney necrosis virus. Putative open reading frames (ORFs) in the ATV sequence identified 24 genes that appear to control virus replication and block antiviral responses. In addition, >50 other putative genes, homologous to ORFs in other iridoviral genomes but of unknown function, were also identified. Sequence comparison performed by dot plot analysis between ATV and itself revealed a conserved 14-bp palindromic repeat within most intragenic regions. Dot plot analysis of ATV vs RRV sequences identified several polymorphisms between the two isolates. Finally, a comparison of ATV and TFV genomic sequences identified genomic rearrangements consistent with the high recombination frequency of iridoviruses. Given the adverse effects that ranavirus infections have on amphibian and fish populations, ATV/RRV sequence information will allow the design of better diagnostic probes for identifying ranavirus infections and extend our understanding of molecular events in ranavirus-infected cells.

Original languageEnglish (US)
Pages (from-to)90-103
Number of pages14
JournalVirology
Volume316
Issue number1
DOIs
StatePublished - Nov 10 2003

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Keywords

  • Ambystoma tigrinum virus
  • Amphibian
  • Dot plot
  • Iridovirus
  • Regina ranavirus

ASJC Scopus subject areas

  • Virology

Cite this

Jancovich, J. K., Mao, J., Chinchar, V. G., Wyatt, C., Case, S. T., Kumar, S., Valente, G., Subramanian, S., Davidson, E. W., Collins, J., & Jacobs, B. (2003). Genomic sequence of a ranavirus (family Iridoviridae) associated with salamander mortalities in North America. Virology, 316(1), 90-103. https://doi.org/10.1016/j.virol.2003.08.001