Research

Marine mimivirus relatives are probably large algal viruses

Adam Monier¹ , Jens Borggaard Larsen² , Ruth-Anne Sandaa² , Gunnar Bratbak² , Jean-Michel Claverie¹ and Hiroyuki Ogata¹

¹  Structural and Genomic Information Laboratory, CNRS-UPR 2589, IBSM, Parc Scientifique de Luminy, 163 avenue de Luminy, Case 934, 13288 Marseille Cedex 9, France

²  Department of Biology, University of Bergen, PO Box 7800, N-5020 Bergen, Norway

author email corresponding author email

Virology Journal 2008, 5:12doi:10.1186/1743-422X-5-12

Published:	23 January 2008

Abstract

Background

Acanthamoeba polyphaga mimivirus is the largest known ds-DNA virus and its 1.2 Mb-genome sequence has revealed many unique features. Mimivirus occupies an independent lineage among eukaryotic viruses and its known hosts include only species from the Acanthamoeba genus. The existence of mimivirus relatives was first suggested by the analysis of the Sargasso Sea metagenomic data.

Results

We now further demonstrate the presence of numerous "mimivirus-like" sequences using a larger marine metagenomic data set. We also show that the DNA polymerase sequences from three algal viruses (CeV01, PpV01, PoV01) infecting different marine algal species (Chrysochromulina ericina, Phaeocystis pouchetii, Pyramimonas orientalis) are very closely related to their homolog in mimivirus.

Conclusion

Our results suggest that the numerous mimivirus-related sequences identified in marine environments are likely to originate from diverse large DNA viruses infecting phytoplankton. Micro-algae thus constitute a new category of potential hosts in which to look for new species of Mimiviridae.