title: Electron-tomographic analysis of intraflagellar transport particle trains in situ.
abstract: Intraflagellar transport (IFT) is the bidirectional movement of multipolypeptide particles between the ciliary membrane and the axonemal microtubules, and is required for the assembly, maintenance, and sensory function of cilia and flagella. In this paper, we present the first high-resolution ultrastructural analysis of trains of flagellar IFT particles, using transmission electron microscopy and electron-tomographic analysis of sections from flat-embedded Chlamydomonas reinhardtii cells. Using wild-type and mutant cells with defects in IFT, we identified two different types of IFT trains: long, narrow trains responsible for anterograde transport; and short, compact trains underlying retrograde IFT. Both types of trains have characteristic repeats and patterns that vary as one sections longitudinally through the trains of particles. The individual IFT particles are highly complex, bridged to each other and to the outer doublet microtubules, and are closely apposed to the inner surface of the flagellar membrane.
authors.affiliation: Dipartimento di Biologia Evolutiva, Università di Siena, 53100 Siena, Italy.
authors.forename: Gaia
authors.initials: G
authors.lastname: Pigino
authors.forename: Stefan
authors.initials: S
authors.lastname: Geimer
authors.forename: Salvatore
authors.initials: S
authors.lastname: Lanzavecchia
authors.forename: Eugenio
authors.initials: E
authors.lastname: Paccagnini
authors.forename: Francesca
authors.initials: F
authors.lastname: Cantele
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Diener
authors.forename: Joel L
authors.initials: JL
authors.lastname: Rosenbaum
authors.forename: Pietro
authors.initials: P
authors.lastname: Lupetti
mesh_terms: D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000648:ultrastructure; D055032:Electron Microscope Tomography; D005407:Flagella / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D009154:Mutation; D010316:Particle Size; D021381:Protein Transport / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*
chemical_list: D020409:Molecular Motor Proteins; D015800:Protozoan Proteins