A giant among viruses could delay ageing and the effects of terminal diseases
A virus with a gigantic genome that infects chalk-covered marine algae contains compounds that could be developed for use in anti-ageing and cancer-inhibiting therapies.
This important discovery was made when researchers at the Plymouth Marine Laboratory and colleagues at the Wellcome Trust Sanger Institute in Cambridge unravelled the genetic code of the largest algal virus, called Emiliania huxleyi virus 86, ever analysed. Their findings are reported in the journal Science, published 12 August 2005.
The team unearthed a cluster of genes responsible for the production of ceramide, a key component of anti-wrinkle and anti-ageing creams. These genes have never before been found in a virus - they are more commonly seen in animal and plant cells.
Ceramide can control mechanisms in the cell that lead to 'programmed cell death'. These processes are important in normal development and in diseases such as cancer. This mechanism is seen when a tadpole's tail is resorbed as it grows into a frog.
"For an invading virus, the ability to control when your host will die and ensure your own survival is quite incredible. Essentially the virus hijacks the cell and slows down the ageing process by keeping it healthy for as long as possible. It uses the cell as a kind of factory to replicate itself and eventually takes over completely, killing off the cell."
Dr WH Wilson
The genome of this virus, which consists of 407,000 letters of genetic code - contains almost as many genes as Mycoplasma, a simple celled organism.
"The genome is remarkably different to other viruses and proved to be a real challenge to decode. The genetic map provides a tantalizing glimpse of the potential benefits locked within, but many of the gene secrets of this mysterious leviathan still remain to be unravelled."
Dr Matthew Holden leader of the Sanger Institute's analysis team
The discovery of viral ceramide will be of great interest to scientists and industries looking for new sources of novel compounds for use in medicines and cosmetics.
"This virus really is a giant. Most viruses only have a few genes - HIV, for example, has only nine - while this algal virus has 472 genes. We've only just scratched the surface - much more work is needed to understand what function most of the genes actually perform."
Dr WH Wilson
The virus appears to infect only the chalk-covered marine algae species (Emiliania huxleyi) that form beautiful 'blooms' on the surface of the sea, soaking up billions of tonnes of carbon dioxide from the atmosphere. Incredibly, during infection the virus is also thought to control climate through production of a gas (dimethyl sulphide) that helps clouds to form.