TY - JOUR TI - Cryo electron tomography with volta phase plate reveals novel structural foundations of the 96-nm axonemal repeat in the pathogen Trypanosoma brucei AU - Imhof, Simon AU - Zhang, Jiayan AU - Wang, Hui AU - Bui, Khanh Huy AU - Nguyen, Hoangkim AU - Atanasov, Ivo AU - Hui, Wong H AU - Yang, Shun Kai AU - Zhou, Z Hong AU - Hill, Kent L A2 - Carter, Andrew P A2 - Kuriyan, John A2 - Engel, Benjamin D A2 - Morriswood, Brooke VL - 8 PY - 2019 DA - 2019/11/11 SP - e52058 C1 - eLife 2019;8:e52058 DO - 10.7554/eLife.52058 UR - https://doi.org/10.7554/eLife.52058 AB - The 96-nm axonemal repeat includes dynein motors and accessory structures as the foundation for motility of eukaryotic flagella and cilia. However, high-resolution 3D axoneme structures are unavailable for organisms among the Excavates, which include pathogens of medical and economic importance. Here we report cryo electron tomography structures of the 96-nm repeat from Trypanosoma brucei, a protozoan parasite in the Excavate lineage that causes African trypanosomiasis. We examined bloodstream and procyclic life cycle stages, and a knockdown lacking DRC11/CMF22 of the nexin dynein regulatory complex (NDRC). Sub-tomogram averaging yields a resolution of 21.8 Å for the 96-nm repeat. We discovered several lineage-specific structures, including novel inter-doublet linkages and microtubule inner proteins (MIPs). We establish that DRC11/CMF22 is required for the NDRC proximal lobe that binds the adjacent doublet microtubule. We propose that lineage-specific elaboration of axoneme structure in T. brucei reflects adaptations to support unique motility needs in diverse host environments. KW - trypanosome KW - cilium KW - parasite KW - motility KW - dynein KW - axoneme JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -