Cryo electron tomography with volta phase plate reveals novel structural foundations of the 96-nm axonemal repeat in the pathogen Trypanosoma brucei

Journal article

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

Authors: Imhof, S; Zhang, J; Wang, H; Bui, KH; Nguyen, H

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: eLife Sciences Publications
• Journal: eLife
• Volume: 8
• Pages: e52058
• Publication date: 2019-11-11
• DOI: 10.7554/elife.52058
• EISSN: 2050-084X
• ISSN: 2050-084X
• Language: English
• Keywords: Dynein; Biology; Lineage (genetic); Motile cilium; Axoneme; Structural biology; Gene; Genetics; Biophysics; Cell biology; Optics; Flagellum; Microtubule; Kinetoplast; Cryo-electron microscopy; DNA; Cryo-electron tomography; Trypanosoma brucei; Physics; Cilium; Tomography