title: Archaeal proviruses TKV4 and MVV extend the PRD1-adenovirus lineage to the phylum Euryarchaeota.
abstract: The viral lineage hypothesis predicting a common origin for viruses that infect hosts residing in different domains of life gains more support as data on viral structures accumulates. One such lineage is the PRD1-adenovirus lineage, which unites icosahedral dsDNA viruses with large facets and a double beta-barrel trimer coat protein. This lineage is represented by a number of viruses infecting bacteria and eukaryotes. However, only one member of the lineage, Sulfolobus turreted icosahedral virus, infecting a crenarchaeal host, has been identified in the domain Archaea. In this study we characterize the genomic sequences of two archaeal proviruses, TKV4 and MVV, integrated into the 5'- and 3'-distal regions of tRNA genes of the euryarchaeal species Thermococcus kodakaraensis KOD1 and Methanococcus voltae A3, respectively. Bioinformatic approaches allowed placement of TKV4 and MVV into the PRD1-adenovirus lineage, thus extending the lineage to the second archaeal phylum, Euryarchaeota.
authors.affiliation: Department of Biological and Environmental Sciences, Biocenter 2, P.O. Box 56 (Viikinkaari 5), FIN-00014 University of Helsinki, Finland. mart.krupovic@helsinki.fi
authors.forename: Mart
authors.initials: M
authors.lastname: Krupovic
authors.forename: Dennis H
authors.initials: DH
authors.lastname: Bamford
mesh_terms: D000256:Adenoviridae / Q000145:classification* / Q000235:genetics*; D000595:Amino Acid Sequence; D025622:Bacteriophage PRD1 / Q000235:genetics; D019641:DNA, Archaeal / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D017017:Methanococcus / Q000821:virology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011533:Proviruses / Q000145:classification* / Q000235:genetics*; D012343:RNA, Transfer / Q000235:genetics; D016415:Sequence Alignment; D016944:Sulfolobus; D019712:Thermococcus / Q000821:virology*
chemical_list: D019641:DNA, Archaeal; D004279:DNA, Viral; D012343:RNA, Transfer