Electron-tomographic analysis of intraflagellar transport particle trains in situ.
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.
Pigino
Gaia
G
Dipartimento di Biologia Evolutiva, Università di Siena, 53100 Siena, Italy.
Geimer
Stefan
S
Lanzavecchia
Salvatore
S
Paccagnini
Eugenio
E
Cantele
Francesca
F
Diener
Dennis R
DR
Rosenbaum
Joel L
JL
Lupetti
Pietro
P
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*
D020409:Molecular Motor Proteins; D015800:Protozoan Proteins