title: Insights into dynamics of mobile genetic elements in hyperthermophilic environments from five new Thermococcus plasmids.
abstract: Mobilome of hyperthermophilic archaea dwelling in deep-sea hydrothermal vents is poorly characterized. To gain insight into genetic diversity and dynamics of mobile genetic elements in these environments we have sequenced five new plasmids from different Thermococcus strains that have been isolated from geographically remote hydrothermal vents. The plasmids were ascribed to two subfamilies, pTN2-like and pEXT9a-like. Gene content and phylogenetic analyses illuminated a robust connection between pTN2-like plasmids and Pyrococcus abyssi virus 1 (PAV1), with roughly half of the viral genome being composed of genes that have homologues in plasmids. Unexpectedly, pEXT9a-like plasmids were found to be closely related to the previously sequenced plasmid pMETVU01 from Methanocaldococcus vulcanius M7. Our data suggests that the latter observation is most compatible with an unprecedented horizontal transfer of a pEXT9a-like plasmid from Thermococcales to Methanococcales. Gene content analysis revealed that thermococcal plasmids encode Hfq-like proteins and toxin-antitoxin (TA) systems of two different families, VapBC and RelBE. Notably, although abundant in archaeal genomes, to our knowledge, TA and hfq-like genes have not been previously found in archaeal plasmids or viruses. Finally, the plasmids described here might prove to be useful in developing new genetic tools for hyperthermophiles.
authors: Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Département de Microbiologie, Institut Pasteur, Paris, France.
authors: Mart
authors: M
authors: Krupovic
authors: Mathieu
authors: M
authors: Gonnet
authors: Wajdi Ben
authors: WB
authors: Hania
authors: Patrick
authors: P
authors: Forterre
authors: Gaël
authors: G
authors: Erauso
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000235:genetics; D023641:Archaeal Viruses / Q000235:genetics; D004251:DNA Transposable Elements / Q000235:genetics*; D019641:DNA, Archaeal / Q000737:chemistry / Q000235:genetics; D023061:Gene Order; D022761:Gene Transfer, Horizontal; D019766:Genes, Archaeal / Q000235:genetics; D060086:Hydrothermal Vents / Q000382:microbiology*; D017015:Methanococcales / Q000145:classification / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D010957:Plasmids / Q000737:chemistry / Q000145:classification / Q000235:genetics*; D043903:Pyrococcus abyssi / Q000821:virology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D018741:Replication Origin / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D019709:Thermococcales / Q000145:classification / Q000235:genetics*; D019712:Thermococcus
chemical_list: D019843:Archaeal Proteins; D004251:DNA Transposable Elements; D019641:DNA, Archaeal; D012336:RNA, Ribosomal, 16S