The kinesin of the flagellum attachment zone in Leishmania is required for cell morphogenesis, cell division and virulence in the mammalian host
Fig 5
Flagellar pocket structure and cell division are perturbed in the FAZ7B null mutant.
Transmission electron micrographs of promastigotes and axenic amastigotes of the FAZ7B KO cell line. Promastigotes (A-B): (A) Abnormal cytoplasmic inclusions are present in the lumen of the FP (white arrows). (B) Rare cells showed abnormal kinetoplasts and/or abnormal basal bodies: here, a mutant cell showing four kDNA networks (of which three are contigous) (white arrow) and four basal bodies asymmetrically distributed (white asterisks). The flagellum structure appears normal (ax, black arrows). Amastigotes (C-K): Abnormal cytoplasmic inclusions were frequently observed in the lumen of the FP (C-G). Depending on the cutting plane, this material could be seen as protrusions of the FP wall inside the lumen of the pocket (D, G; white arrows). (G) An amastigote cell showing two nuclei and six transversal sections of flagella in a single FP and two flagella in another one. (H) Longitudinal section of a dividing amastigote, with two nuclei and only one kinetoplast and one FP visible on this cutting plane. On the left side, a portion of cytoplasm apparently devoid of nucleus but containing lipid bodies and organites shows incomplete separation from the ‘donor’ cell, with discontinuous plasma membrane and cortical microtubules (white arrows), forming a cytoplast (cp, black arrow). (I-K) A transversal section of a dividing FAZ7B-KO amastigote showing multiple FPs each containing one or two flagella. At least three partially separated cell bodies can be distinguished. The cortical microtubule network is in place but the plasma membrane shows incomplete separation (J, white arrows). The microtubule quartet is clearly seen close to most flagella (J, black arrowheads). The flagellum structure in transversal sections appears normal. n: nucleus; k: kinetoplast; ax: Axoneme; cp: cytoplast. Scale bars: 0.5 μm.