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International Summer School
From Genome to Life:
Structural, Functional and Evolutionary approaches
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FORTERRE
Patrick |
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Institut de Génétique et Microbiologie -, Université Paris Sud -, 91405 Orsay, France title: Origin and evolution of DNA and DNA replication mechanisms : the viral connection Patrick Forterre, Jonathan Filée and Hannu Myllykallio Comparative
genomics associated to molecular phylogenetic
analyses have produced during the last decade a
wealth of new data that can be tentatively used to
reconstruct early cellular evolution (1). In
particular, it is now clear that essential
enzymatic activities required for production and
replication of DNA have been invented several times
independently. For example, we have recently
identified two evolutionary unrelated families of
type II DNA topoisomerases and thymidylate
synthases (2,3). It is also evident that at least
two different mechanisms for DNA replication are
present in the cellular world (4) and that many DNA
viruses encode their own version of DNA replication
mechanism. We have recently detected a case of non
orthologous displacement of a bacterial DNA
polymerase by a viral DNA polymerase in
mitochondria (5). Non orthologous displacement of
cellular proteins by viral functional analogs could
explain why DNA replication proteins in Archaea and
Bacteria are so different (6), despite a similar
mode of replication in the two prokaryotic domains
(7). These observations suggest an important role
for viruses in the origin and evolution of DNA and
DNA replication mechanisms.
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