title: Noncanonical cell-to-cell DNA transfer in Thermus spp. is insensitive to argonaute-mediated interference.
abstract: Horizontal gene transfer drives the rapid evolution of bacterial populations. Classical processes that promote the lateral flow of genetic information are conserved throughout the prokaryotic world. However, some species have nonconserved transfer mechanisms that are not well known. This is the case for the ancient extreme thermophile Thermus thermophilus. In this work, we show that T. thermophilus strains are capable of exchanging large DNA fragments by a novel mechanism that requires cell-to-cell contacts and employs components of the natural transformation machinery. This process facilitates the bidirectional transfer of virtually any DNA locus but favors by 10-fold loci found in the megaplasmid over those in the chromosome. In contrast to naked DNA acquisition by transformation, the system does not activate the recently described DNA-DNA interference mechanism mediated by the prokaryotic Argonaute protein, thus allowing the organism to distinguish between DNA transferred from a mate and exogenous DNA acquired from unknown hosts. This Argonaute-mediated discrimination may be tentatively viewed as a strategy for safe sharing of potentially "useful" traits by the components of a given population of Thermus spp. without increasing the genome sizes of its individuals.
authors.affiliation: Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Alba
authors.initials: A
authors.lastname: Blesa
authors.affiliation: Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Carolina Elvira
authors.initials: CE
authors.lastname: César
authors.affiliation: Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany.
authors.forename: Beate
authors.initials: B
authors.lastname: Averhoff
authors.affiliation: Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain jose.berenguer@uam.es.
authors.forename: José
authors.initials: J
authors.lastname: Berenguer
mesh_terms: D060565:Argonaute Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D022761:Gene Transfer, Horizontal / Q000502:physiology*; D010957:Plasmids; D016963:Thermus thermophilus / Q000166:cytology / Q000235:genetics / Q000378:metabolism*
chemical_list: D060565:Argonaute Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial