290 Nucleic Acids Research, 2011, Vol. 39, No. 1 P.-E.G. supervised the project. C.C., M.-F.O’D. and P.- E.G. were involved in writing the manuscript. FUNDING CNRS, the University of Toulouse and the French National Research Agency (ANR – RIBEUC project); P.E.G. is a fellow of the Institut Universitaire de France; doctoral fellowship from the Ministe` re de l’Enseignement Sup e´rieur et de la Recherche and from the Association pour la Recherche sur le Cancer (to C.C.). Funding for open access charge: CNRS. Conﬂict of interest statement. None declared. REFERENCES 1. Fatica,A. and Tollervey,D. (2002) Making ribosomes. Curr. Opin. Cell Biol., 14, 313–318. 2. Fromont-Racine,M., Senger,B., Saveanu,C. and Fasiolo,F. (2003) Ribosome assembly in eukaryotes. Gene, 313, 17–42. 3. Schafer,T., Strauss,D., Petfalski,E., Tollervey,D. and Hurt,E. (2003) The path from nucleolar 90S to cytoplasmic 40S pre-ribosomes. EMBO J., 22, 1370–1380. 4. Tschochner,H. and Hurt,E. 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