title: In sílico identification and characterization of putative Dot/Icm secreted virulence effectors in the fish pathogen Piscirickettsia salmonis.
abstract: Piscirickettsia salmonis seriously affects the Chilean salmon industry. The bacterium is phylogenetically related to Legionella pneumophila and Coxiella burnetii, sharing a Dot/Icm secretion system with them. Although it is well documented that L. pneumophila and C. burnetii secrete different virulence effectors via this Dot/Icm system in order to attenuate host cell responses, to date there have been no reported virulence effectors secreted by the Dot/Icm system of P. salmonis. Using several annotations of P. salmonis genome, here we report an in silico analyses of 4 putative Dot/Icm effectors. Three of them contain ankyrin repeat domains and the typical conserved 3D structures of this protein family. The fourth one is highly similar to one of the Dot/Icm-dependent effectors of L. pneumophila. Additionally, all the potential P. salmonis effectors contain a classical Dot/Icm secretion signal in their C-terminus, consisting of: an E-Block, a hydrophobic residue in -3 or -4 and an electronegative charge. Finally, qPCR analysis demonstrated that these proteins are overexpressed early in infection, perhaps contributing to the generation of a replicative vacuole, a key step in the neutralizing strategy proposed for the Dot/Icm system. In summary, this report identifies four Dot/Icm-dependent effectors in P. salmonis.
authors.affiliation: Laboratorio de Patógenos Acuícolas, Núcleo de Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Chile; Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Av. Universidad 330, Curauma, Valparaíso, Chile. Electronic address: alvaro.labra@pucv.cl.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Labra
authors.affiliation: Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Av. Universidad 330, Curauma, Valparaíso, Chile. Electronic address: oscar.arredondo.zelada@gmail.com.
authors.forename: Oscar
authors.initials: O
authors.lastname: Arredondo-Zelada
authors.affiliation: Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Av. Universidad 330, Curauma, Valparaíso, Chile. Electronic address: patricio.flores@pucv.cl.
authors.forename: Patricio
authors.initials: P
authors.lastname: Flores-Herrera
authors.affiliation: Laboratorio de Patógenos Acuícolas, Núcleo de Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Chile; Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Av. Universidad 330, Curauma, Valparaíso, Chile; Fraunhofer Chile Research Foundation, Center for Systems Biotechnology, Santiago, Chile. Electronic address: sergio.marshall@pucv.cl.
authors.forename: Sergio H
authors.initials: SH
authors.lastname: Marshall
authors.affiliation: Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Av. Universidad 330, Curauma, Valparaíso, Chile. Electronic address: fernando.gomez@pucv.cl.
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Gómez
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019295:Computational Biology / Q000379:methods; D005393:Fish Diseases / Q000382:microbiology; D005399:Fishes / Q000382:microbiology; D015870:Gene Expression; D016680:Genome, Bacterial; D008958:Models, Molecular; D016366:Open Reading Frames; D053522:Piscirickettsia / Q000145:classification* / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D021381:Protein Transport; D000069319:Type IV Secretion Systems; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D000069319:Type IV Secretion Systems