From small hosts come big viruses: the complete genome of a second Ostreococcus tauri virus, OtV-1

Environ Microbiol. 2009 Nov;11(11):2821-39. doi: 10.1111/j.1462-2920.2009.01991.x. Epub 2009 Jul 23.


Ostreococcus tauri virus (OtV-1) is a large double-stranded DNA virus and a prospective member of the family Phycodnaviridae, genus Prasinovirus. OtV-1 infects the unicellular marine green alga O. tauri, the smallest known free-living eukaryote. Here we present the 191 761 base pair genome sequence of OtV-1, which has 232 putative protein-encoding and 4 tRNA-encoding genes. Approximately 31% of the viral gene products exhibit a similarity to proteins of known functions in public databases. These include a variety of unexpected genes, for example, a PhoH-like protein, a N-myristoyltransferase, a 3-dehydroquinate synthase, a number of glycosyltransferases and methyltransferases, a prolyl 4-hydroxylase, 6-phosphofructokinase and a total of 8 capsid proteins. A total of 11 predicted genes share homology with genes found in the Ostreococcus host genome. In addition, an intein was identified in the DNA polymerase gene of OtV-1. This is the first report of an intein in the genome of a virus that infects O. tauri. Fifteen core genes common to nuclear-cytoplasmic large dsDNA virus (NCLDV) genomes were identified in the OtV-1 genome. This new sequence data may help to redefine the classification of the core genes of these viruses and shed new light on their evolutionary history.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Chlorophyta / virology*
  • DNA, Viral / chemistry*
  • DNA, Viral / genetics*
  • Genes, Viral
  • Genome, Viral*
  • Microscopy, Electron, Transmission
  • Molecular Sequence Data
  • Phycodnaviridae / genetics*
  • Phycodnaviridae / isolation & purification
  • Phylogeny
  • Sequence Analysis, DNA*
  • Sequence Homology, Amino Acid
  • Viral Proteins / genetics
  • Virion / ultrastructure


  • DNA, Viral
  • Viral Proteins

Associated data

  • GENBANK/FN386611
  • RefSeq/NC_013288