Patrick Forterre

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The archaeal domain is currently divided into two major phyla, the Euryarchaeota and Crenarchaeota. During the past few years, diverse groups of uncultivated mesophilic archaea have been discovered and affiliated with the Crenarchaeota. It was recently recognized that these archaea have a major role in geochemical cycles. Based on the first genome sequence(More)
Type II topoisomerases help regulate DNA topology during transcription, replication and recombination by catalysing DNA strand transfer through transient double-stranded breaks. All type II topoisomerases described so far are members of a single protein family. We have cloned and sequenced the genes encoding the A and B subunits of topoisomerase II from the(More)
Cultivable archaeal species are assigned to two phyla - the Crenarchaeota and the Euryarchaeota - by a number of important genetic differences, and this ancient split is strongly supported by phylogenetic analysis. The recently described hyperthermophile Nanoarchaeum equitans, harboring the smallest cellular genome ever sequenced (480 kb), has been(More)
Several composite universal trees connected by an ancestral gene duplication have been used to root the universal tree of life. In all cases, this root turned out to be in the eubacterial branch. However, the validity of results obtained from comparative sequence analysis has recently been questioned, in particular, in the case of ancient phylogenies. For(More)
DNA viruses of the Archaea have highly diverse and often exceptionally complex morphotypes. Many have been isolated from geothermally heated hot environments, raising intriguing questions about their origins, and contradicting the widespread notion of limited biodiversity in extreme environments. Here, we provide a unifying view on archaeal viruses, and(More)
Little more than 30 years since the discovery of the Archaea, over one hundred archaeal genome sequences are now publicly available, of which ∼40% have been released in the last two years. Their analysis provides an increasingly complex picture of archaeal phylogeny and evolution with the proposal of new major phyla, such as the Thaumarchaeota, and(More)
Viruses are obligate parasites of Eukarya, Archaea and Bacteria. Acanthamoeba polyphaga mimivirus (APMV) is the largest known virus; it grows only in amoeba and is visible under the optical microscope. Mimivirus possesses a 1,185-kilobase double-stranded linear chromosome whose coding capacity is greater than that of numerous bacteria and archaea1, 2, 3.(More)
Despite a rapid increase in the amount of available archaeal sequence information, little is known about the duplication of genetic material in the third domain of life. We identified a single origin of bidirectional replication in Pyrococcus abyssi by means of in silico analyses of cumulative oligomer skew and the identification of an early replicating(More)
Although deoxythymidylate cannot be provided directly by ribonucleotide reductase, the gene encoding thymidylate synthase ThyA is absent from the genomes of a large number of nonsymbiotic microbes. We show that ThyX (Thy1) proteins of previously unknown function form a large and distinct class of thymidylate synthases. ThyX has a wide but sporadic(More)
I discuss here the possibility that Eukarya originated from the engulfment of a thaumarchaeon by a PCV (Planctomycetes, Verrucomicrobia, Chlamydiae) bacterium, followed by invasions of NCLDV and retroviruses. The thaumarchaeon provided both informational and operational proteins (actins, ESCRT proteins), including some essential proteins absent in other(More)