Miniature RNAs are embedded in an exceptionally protein-rich mitoribosome via an elaborate assembly pathway

0574463 - BC 2024 RIV US eng J - Journal Article
Valach, M. - Benz, Corinna - Aguilar, L.C. - Gahura, Ondřej - Faktorová, Drahomíra - Zíková, Alena - Oeffinger, M. - Burger, G. - Gray, M.W. - Lukeš, Julius
Miniature RNAs are embedded in an exceptionally protein-rich mitoribosome via an elaborate assembly pathway.
Nucleic Acids Research. Roč. 51, č. 12 (2023), s. 6443-6460. ISSN 0305-1048. E-ISSN 1362-4962
R&D Projects: GA ČR(CZ) GX23-06479X; GA ČR(CZ) GJ20-04150Y; GA MŠMT(CZ) EF16_019/0000759
EU Projects: European Commission(XE) 101044951 - MitoSignal
Grant - others:Gordon and Betty Moore Foundation(US) GBMF9354
Institutional support: RVO:60077344
Keywords : RNAs * protein-rich mitoribosome
OECD category: Microbiology
Impact factor: 14.9, year: 2022
Method of publishing: Open access
https://academic.oup.com/nar/article/51/12/6443/7173778?login=true

The mitochondrial ribosome (mitoribosome) has diverged drastically from its evolutionary progenitor, the bacterial ribosome. Structural and compositional diversity is particularly striking in the phylum Euglenozoa, with an extraordinary protein gain in the mitoribosome of kinetoplastid protists. Here we report an even more complex mitoribosome in diplonemids, the sister-group of kinetoplastids. Affinity pulldown of mitoribosomal complexes from Diplonema papillatum, the diplonemid type species, demonstrates that they have a mass of > 5 MDa, contain as many as 130 integral proteins, and exhibit a protein-to-RNA ratio of 11:1. This unusual composition reflects unprecedented structural reduction of ribosomal RNAs, increased size of canonical mitoribosomal proteins, and accretion of three dozen lineage-specific components. In addition, we identified >50 candidate assembly factors, around half of which contribute to early mitoribosome maturation steps. Because little is known about early assembly stages even in model organisms, our investigation of the diplonemid mitoribosome illuminates this process. Together, our results provide a foundation for understanding how runaway evolutionary divergence shapes both biogenesis and function of a complex molecular machine.
Permanent Link: https://hdl.handle.net/11104/0344803