Life with eight flagella: flagellar assembly and division in Giardia

Flagellar movement in Giardia, a common intestinal parasitic protist, is crucial to its survival in the host Each axoneme is unique in possessing a long, cytoplasmic portion as well as a membrane-bound portion. Intraflagellar transport (IFT) is required for the assembly of membrane-bound regions, yet the cytoplasmic regions may be assembled by IFT-independent mechanisms Steady-state axoneme length is maintained by IFT and by intrinsic and active microtubule dynamics Following mitosis and before their segregation, giardial flagella undergo a multigenerational division cycle in which the parental eight flagella migrate and reposition to different cellular locations, eight new flagella are assembled de novo Each daughter cell thus inherits four mature and four newly synthesized flagella