Coccolithovirus

Emiliania huxleyi virus 86 (EhV-86)

Coccolithovirus is a giant double-stranded DNA virus that infects Emiliania huxleyi, a species of coccolithophore. Its genome is 407,339 base pairs long with a G+C content of 41.1%, and contains 472 predicted coding sequences.

Wilson and his team at the Marine Biological Association (MBA), University of East Anglia and Plymouth Marine Laboratory (PML), first observed the virus in 1999. Later in the summer of 2005 researchers at the Plymouth Marine Laboratory (Willie Wilson et al.) and at the Sanger Institute (Holden et al.) sequenced the genome for the EhV-86 strain finding it to have 472 protein-coding genes making it a "giant-virus", and the largest known marine virus by genome.

From initial investigation of the Coccolithoviruses genome, a sequence of genes responsible for production of ceramide was discovered. Ceramide is a controlling factor in cell death, and it is currently thought that Coccolithovirus uses this to prolong the life of Emiliania huxleyi while it uses the host cell to replicate. This is a unique ability unseen in any viral genome to date.