title: Basal body duplication in Paramecium: the key role of Bld10 in assembly and stability of the cartwheel.
abstract: Basal bodies which nucleate cilia and flagella, and centrioles which organize centrosomes share the same architecture characterized by the ninefold symmetry of their microtubular shaft. Among the conserved proteins involved in the biogenesis of the canonical 9-triplet centriolar structures, Sas-6 and Bld10 proteins have been shown to play central roles in the early steps of assembly and in establishment/stabilization of the ninefold symmetry. Using fluorescent tagged proteins and RNAi to study the localization and function of these two proteins in Paramecium, we focused on the early effects of their depletion, the consequences of their overexpression and their functional interdependence. We find that both genes are essential and their depletion affects cartwheel assembly and hence basal body duplication. We also show that, contrary to Sas6p, Bld10p is not directly responsible for the establishment of the ninefold symmetry, but is required not only for new basal body assembly and stability but also for Sas6p maintenance at mature basal bodies. Finally, ultrastructural analysis of cells overexpressing either protein revealed two types of early assembly intermediates, hub-like structures and generative discs, suggesting a conserved scaffolding process.
authors.affiliation: Department of Cell Biology, M. Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Maria
authors.initials: M
authors.lastname: Jerka-Dziadosz
authors.forename: Delphine
authors.initials: D
authors.lastname: Gogendeau
authors.forename: Catherine
authors.initials: C
authors.lastname: Klotz
authors.forename: Jean
authors.initials: J
authors.lastname: Cohen
authors.forename: Janine
authors.initials: J
authors.lastname: Beisson
authors.forename: France
authors.initials: F
authors.lastname: Koll
mesh_terms: D000818:Animals; D002502:Centrioles / Q000235:genetics* / Q000648:ultrastructure; D002923:Cilia / Q000378:metabolism*; D005407:Flagella / Q000378:metabolism* / Q000648:ultrastructure; D049452:Green Fluorescent Proteins / Q000378:metabolism; D010247:Paramecium / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D015800:Protozoan Proteins / Q000378:metabolism / Q000502:physiology*; D034622:RNA Interference
chemical_list: D015800:Protozoan Proteins; D049452:Green Fluorescent Proteins