title: Sequence of plasmid pGT5 from the archaeon Pyrococcus abyssi: evidence for rolling-circle replication in a hyperthermophile.
abstract: The plasmid pGT5 (3,444 bp) from the hyperthermophilic archaeon Pyrococcus abyssi GE5 has been completely sequenced. Two major open reading frames with a good coding probability are located on the same strand and cover 85% of the total sequence. The larger open reading frame encodes a putative polypeptide which exhibits sequence similarity with Rep proteins of plasmids using the rolling-circle mechanism for replication. Upstream of this open reading frame, we have detected an 11-bp motif identical to the double-stranded origin of several bacterial plasmids that replicate via the rolling-circle mechanism. A putative single-stranded origin exhibits similarities both to bacterial primosome-dependent single-stranded initiation sites and to bacterial primase (dnaG) start sites. A single-stranded form of pGT5 corresponding to the plus strand was detected in cells of P. abyssi. These data indicate that pGT5 replicates via the rolling-circle mechanism and suggest that members of the domain Archaea contain homologs of several bacterial proteins involved in chromosomal DNA replication. Phylogenetic analysis of Rep proteins from rolling-circle replicons suggest that diverse families diverged before the separation of the domains Archaea, Bacteria, and Eucarya.
authors.affiliation: Station Biologique de Roscoff, UPR 9042 Centre National de la Recherche Scientifique, Université Paris-Sud, France.
authors.forename: G
authors.initials: G
authors.lastname: Erauso
authors.forename: S
authors.initials: S
authors.lastname: Marsin
authors.forename: N
authors.initials: N
authors.lastname: Benbouzid-Rollet
authors.forename: M F
authors.initials: MF
authors.lastname: Baucher
authors.forename: T
authors.initials: T
authors.lastname: Barbeyron
authors.forename: Y
authors.initials: Y
authors.lastname: Zivanovic
authors.forename: D
authors.initials: D
authors.lastname: Prieur
authors.forename: P
authors.initials: P
authors.lastname: Forterre
mesh_terms: D000595:Amino Acid Sequence; D001105:Archaea / Q000235:genetics*; D001483:Base Sequence; D004261:DNA Replication; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D010957:Plasmids