300
J. Querellou et al.
era and its associated culture independent approaches has opened up the field of
marine virology for exploitation. No one gene is common to all viruses and random sequencing of the viral fraction of the ocean has revealed a plethora of genetic
diversity that has so far been inaccessible (Angly et al. 2006).
In the past, viruses were thought of as simple, self propagating bags of genes.
The discovery of giant viruses in particular has turned this notion on its head and
has shown that viruses can often have the ability to manipulate and control complex
metabolic pathways using enzymes encoded on their own genomes (Raoult et al.
2004, Wilson et al. 2005, la Scola et al. 2008). For example, proteins of viral origin
feature heavily in the molecular biologists armoury. Proteins from bacteriophage T4
(which infects E. coli) such as its DNA ligase, polynucleotide kinase, DNA polymerase are all commercially available for cloning purposes. RNA polymerases from
T7, phi6 and SP6 are in common usage. Reverse transcriptase (RNA-directed DNA
polymerase, a function only found in viruses thus far) from Avian Myeloblastosis
Virus and Moloney Murine Leukemia Virus are standard enzymes for making cDNA
from RNA templates. Whilst none of these viruses are marine in origin, these examples demonstrate that viruses harbour useful, efficient and exploitable enzymes.
Few marine viruses have been studied intensively, yet the handful that have been
have revealed considerable biotechnological potential (Allen and Wilson 2008).
For example, the coccolithovirus EhV-86 has a genome that appears to encode a
near complete ceramide synthesis pathway (a transferase, elongation protein, phosphatase and three desaturases) (Wilson et al. 2005, Han et al. 2006). Ceramides are
components of the plasma membrane and has been made use of as anti-aging component commonly found in cosmetics. This newly discovered viral pathway is being
investigated not only for its academic relevance but also for potential commercial
exploitation. Also found on this genome are a lipase and esterase (as well as numerous nucleases and proteases) which may have biocatalytic applications (Allen et al.
2006b). Yet, even with the briefest of glimpses at viral genetic diversity, we have
realised how little we know about how these organisms function: typically 80% of
newly derived sequence of viral origin can be unique and have no known function
associated with it (Suttle 2005). Clearly, the vast majority of these novel genes must
be of some use to viruses and yet we have no clues as to their function and relevance (Yin and Fischer 2008). As the functions of these genes are unravelled, we
predict new and exciting biotechnological applications exploiting novel biochemical
pathways and reactions.
Inteins have gained increasing attention since their discovery (Gogarten and
Hilario 2006). An intein is a self splicing segment of a protein which has the ability
to excise itself and rejoin the adjacent segments of the protein with a peptide bond.
They have important biotechnological applications for protein expression, synthesis,
purification and labelling (Perler 2002). Inteins have been found throughout all kingdoms of life, but are now being found to be increasingly common in marine viruses.
Inteins have been found in Heterosigma akashiwo viruses (Nagasaki et al. 2005), in
some strains of coccolithoviruses (Allen et al. 2006a; Goodwin et al. 2006), as well
as in the mimivirus (Ogata et al. 2005), relatives of which (with intein fragments)
have been found in the Sargasso Sea metagenome dataset (Ghedin and Claverie
2005).
J. Querellou et al.
era and its associated culture independent approaches has opened up the field of
marine virology for exploitation. No one gene is common to all viruses and random sequencing of the viral fraction of the ocean has revealed a plethora of genetic
diversity that has so far been inaccessible (Angly et al. 2006).
In the past, viruses were thought of as simple, self propagating bags of genes.
The discovery of giant viruses in particular has turned this notion on its head and
has shown that viruses can often have the ability to manipulate and control complex
metabolic pathways using enzymes encoded on their own genomes (Raoult et al.
2004, Wilson et al. 2005, la Scola et al. 2008). For example, proteins of viral origin
feature heavily in the molecular biologists armoury. Proteins from bacteriophage T4
(which infects E. coli) such as its DNA ligase, polynucleotide kinase, DNA polymerase are all commercially available for cloning purposes. RNA polymerases from
T7, phi6 and SP6 are in common usage. Reverse transcriptase (RNA-directed DNA
polymerase, a function only found in viruses thus far) from Avian Myeloblastosis
Virus and Moloney Murine Leukemia Virus are standard enzymes for making cDNA
from RNA templates. Whilst none of these viruses are marine in origin, these examples demonstrate that viruses harbour useful, efficient and exploitable enzymes.
Few marine viruses have been studied intensively, yet the handful that have been
have revealed considerable biotechnological potential (Allen and Wilson 2008).
For example, the coccolithovirus EhV-86 has a genome that appears to encode a
near complete ceramide synthesis pathway (a transferase, elongation protein, phosphatase and three desaturases) (Wilson et al. 2005, Han et al. 2006). Ceramides are
components of the plasma membrane and has been made use of as anti-aging component commonly found in cosmetics. This newly discovered viral pathway is being
investigated not only for its academic relevance but also for potential commercial
exploitation. Also found on this genome are a lipase and esterase (as well as numerous nucleases and proteases) which may have biocatalytic applications (Allen et al.
2006b). Yet, even with the briefest of glimpses at viral genetic diversity, we have
realised how little we know about how these organisms function: typically 80% of
newly derived sequence of viral origin can be unique and have no known function
associated with it (Suttle 2005). Clearly, the vast majority of these novel genes must
be of some use to viruses and yet we have no clues as to their function and relevance (Yin and Fischer 2008). As the functions of these genes are unravelled, we
predict new and exciting biotechnological applications exploiting novel biochemical
pathways and reactions.
Inteins have gained increasing attention since their discovery (Gogarten and
Hilario 2006). An intein is a self splicing segment of a protein which has the ability
to excise itself and rejoin the adjacent segments of the protein with a peptide bond.
They have important biotechnological applications for protein expression, synthesis,
purification and labelling (Perler 2002). Inteins have been found throughout all kingdoms of life, but are now being found to be increasingly common in marine viruses.
Inteins have been found in Heterosigma akashiwo viruses (Nagasaki et al. 2005), in
some strains of coccolithoviruses (Allen et al. 2006a; Goodwin et al. 2006), as well
as in the mimivirus (Ogata et al. 2005), relatives of which (with intein fragments)
have been found in the Sargasso Sea metagenome dataset (Ghedin and Claverie
2005).