Cryo electron tomography with Volta phase plate reveals novel structural foundations of the 96-nm axonemal repeat in the pathogen Trypanosoma brucei
- University of California, Los Angeles, United States
- McGill University, Canada
Abstract
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 structure 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.
Data availability
All data generated or analyzed during this study are included in the manuscript ans supporting files. Source data files have been provided for Figure 2F and Figure 3-Suppl. 4. The cryoET sub-tomogram average maps have been deposited in the EM Data Bank under the accession codes EMD-20012, EMD-20013 and EMD-20014, for the wild-type bloodstream form, wild-type and DRC11-knock-down procyclic form, respectively.
Article and author information
Author details
Funding
Swiss National Science Foundation (P300PA_174358)
- Simon Imhof
National Science Foundation (DBI-1338135)
- Z Hong Zhou
National Institutes of Health (R01GM071940)
- Jiyan Zhang
- Hui Wang
- Ivo Atanosov
- Wong H Hui
- Z Hong Zhou
National Institutes of Health (S10RR23057)
- Z Hong Zhou
National Science Foundation (DMR-1548924)
- Z Hong Zhou
National Institutes of Health (GM007185)
- Khanh Huy Bui
National Institutes of Health (AI052348)
- Simon Imhof
- Hoangkim Nguyen
- Kent L Hill
Swiss National Science Foundation (P2BEP3_162094)
- Simon Imhof
National Institutes of Health (S10OD018111)
- Z Hong Zhou
National Institutes of Health (U24GM116792)
- Z Hong Zhou
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2019, Imhof et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Cryo electron tomography with Volta phase plate reveals novel structural foundations of the 96-nm axonemal repeat in the pathogen Trypanosoma brucei
eLife 8:e52058.
https://doi.org/10.7554/eLife.52058
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