Selfish DNA in Protein-Coding Genes of Rickettsia
Hiroyuki Ogata,1
Stéphane Audic,1
Valérie Barbe,2
François Artiguenave,2
Pierre-Edouard Fournier,3
Didier Raoult,3
Jean-Michel Claverie1*
Rickettsia conorii, the aetiological agent of
Mediterranean spotted fever, is an intracellular bacterium transmitted
by ticks. Preliminary analyses of the nearly complete genome sequence
of R. conorii have revealed 44 occurrences of a previously
undescribed palindromic repeat (150 base pairs long) throughout the
genome. Unexpectedly, this repeat was found inserted in-frame within 19 different R. conorii open reading frames likely to encode
functional proteins. We found the same repeat in proteins of other
Rickettsia species. The finding of a mobile element inserted
in many unrelated genes suggests the potential role of selfish DNA in
the creation of new protein sequences.
1 Information Génétique & Structurale, CNRS-AVENTIS UMR 1889, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
2 Genoscope, Centre
National de Séquençage, 2 rue Gaston Crémieux, 91000 Evry, France.
3 Unité des Rickettsies,
Université de la Méditerranée, Faculté de
Médecine, CNRS UPRES A 6020, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 05, France.
*
To whom correspondence should be addressed. E-mail:
jean-michel.claverie{at}igs.cnrs-mrs.fr
