title: Sas-4 proteins are required during basal body duplication in Paramecium.
abstract: Centrioles and basal bodies are structurally related organelles composed of nine microtubule (MT) triplets. Studies performed in Caenorhabditis elegans embryos have shown that centriole duplication takes place in sequential way, in which different proteins are recruited in a specific order to assemble a procentriole. ZYG-1 initiates centriole duplication by triggering the recruitment of a complex of SAS-5 and SAS-6, which then recruits the final player, SAS-4, to allow the incorporation of MT singlets. It is thought that a similar mechanism (that also involves additional proteins) is present in other animal cells, but it remains to be investigated whether the same players and their ascribed functions are conserved during basal body duplication in cells that exclusively contain basal bodies. To investigate this question, we have used the multiciliated protist Paramecium tetraurelia. Here we show that in the absence of PtSas4, two types of defects in basal body duplication can be identified. In the majority of cases, the germinative disk and cartwheel, the first structures assembled during duplication, are not detected. In addition, if daughter basal bodies were formed, they invariably had defects in MT recruitment. Our results suggest that PtSas4 has a broader function than its animal orthologues.
authors.affiliation: Institut Curie, Center de Recherche, Paris F-75248, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Gogendeau
authors.forename: Ilse
authors.initials: I
authors.lastname: Hurbain
authors.forename: Graca
authors.initials: G
authors.lastname: Raposo
authors.forename: Jean
authors.initials: J
authors.lastname: Cohen
authors.forename: France
authors.initials: F
authors.lastname: Koll
authors.forename: Renata
authors.initials: R
authors.lastname: Basto
mesh_terms: D000818:Animals; D002502:Centrioles / Q000378:metabolism* / Q000648:ultrastructure; D002923:Cilia / Q000502:physiology / Q000648:ultrastructure; D020868:Gene Silencing; D006801:Humans; D010247:Paramecium / Q000166:cytology*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014404:Tubulin / Q000378:metabolism
chemical_list: D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D014404:Tubulin