title: Tropheryma whipplei Twist: a human pathogenic Actinobacteria with a reduced genome.
abstract: The human pathogen Tropheryma whipplei is the only known reduced genome species (<1 Mb) within the Actinobacteria [high G+C Gram-positive bacteria]. We present the sequence of the 927303-bp circular genome of T. whipplei Twist strain, encoding 808 predicted protein-coding genes. Specific genome features include deficiencies in amino acid metabolisms, the lack of clear thioredoxin and thioredoxin reductase homologs, and a mutation in DNA gyrase predicting a resistance to quinolone antibiotics. Moreover, the alignment of the two available T. whipplei genome sequences (Twist vs. TW08/27) revealed a large chromosomal inversion the extremities of which are located within two paralogous genes. These genes belong to a large cell-surface protein family defined by the presence of a common repeat highly conserved at the nucleotide level. The repeats appear to trigger frequent genome rearrangements in T. whipplei, potentially resulting in the expression of different subsets of cell surface proteins. This might represent a new mechanism for evading host defenses. The T. whipplei genome sequence was also compared to other reduced bacterial genomes to examine the generality of previously detected features. The analysis of the genome sequence of this previously largely unknown human pathogen is now guiding the development of molecular diagnostic tools and more convenient culture conditions.
authors.affiliation: Unité des Rickettsies, Faculté de Médecine, CNRS UMR6020, Université de la Méditerranée, 13385 Marseille Cedex 05, France. Dadier.Raoult@medicine.univ-mrs.fr
authors.forename: Didier
authors.initials: D
authors.lastname: Raoult
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ogata
authors.forename: Stephane
authors.initials: S
authors.lastname: Audic
authors.forename: Catherine
authors.initials: C
authors.lastname: Robert
authors.forename: Karsten
authors.initials: K
authors.lastname: Suhre
authors.forename: Michel
authors.initials: M
authors.lastname: Drancourt
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Claverie
mesh_terms: D000192:Actinomycetales / Q000235:genetics* / Q000472:pathogenicity*; D000193:Actinomycetales Infections / Q000235:genetics; D000596:Amino Acids / Q000378:metabolism; D001482:Base Composition; D004269:DNA, Bacterial / Q000032:analysis; D004734:Energy Metabolism / Q000235:genetics; D020862:GC Rich Sequence / Q000235:genetics; D022761:Gene Transfer, Horizontal / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics / Q000502:physiology; D016680:Genome, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D011237:Predictive Value of Tests; D011544:Pseudogenes / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D000596:Amino Acids; D004269:DNA, Bacterial