Ciliate mitoribosome illuminates evolutionary steps of mitochondrial translation
To understand the steps involved in the evolution of translation, we used Tetrahymena thermophila, a ciliate with high coding capacity of the mitochondrial genome, as the model organism and characterized its mitochondrial ribosome (mitoribosome) using cryo-EM. The structure of the mitoribosome revea...
Main Authors: | , |
---|---|
Format: | Article |
Language: | English |
Published: |
eLife Sciences Publications Ltd
2020-06-01
|
Series: | eLife |
Subjects: | |
Online Access: | https://elifesciences.org/articles/59264 |
id |
doaj-c36e8e8ad2274e9f83f2f74d772f6694 |
---|---|
record_format |
Article |
spelling |
doaj-c36e8e8ad2274e9f83f2f74d772f66942021-05-05T21:13:20ZengeLife Sciences Publications LtdeLife2050-084X2020-06-01910.7554/eLife.59264Ciliate mitoribosome illuminates evolutionary steps of mitochondrial translationVictor Tobiasson0https://orcid.org/0000-0001-8920-017XAlexey Amunts1https://orcid.org/0000-0002-5302-1740Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, SwedenScience for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, SwedenTo understand the steps involved in the evolution of translation, we used Tetrahymena thermophila, a ciliate with high coding capacity of the mitochondrial genome, as the model organism and characterized its mitochondrial ribosome (mitoribosome) using cryo-EM. The structure of the mitoribosome reveals an assembly of 94-ribosomal proteins and four-rRNAs with an additional protein mass of ~700 kDa on the small subunit, while the large subunit lacks 5S rRNA. The structure also shows that the small subunit head is constrained, tRNA binding sites are formed by mitochondria-specific protein elements, conserved protein bS1 is excluded, and bacterial RNA polymerase binding site is blocked. We provide evidence for anintrinsic protein targeting system through visualization of mitochondria-specific mL105 by the exit tunnel that would facilitate the recruitment of a nascent polypeptide. Functional protein uS3m is encoded by three complementary genes from the nucleus and mitochondrion, establishing a link between genetic drift and mitochondrial translation. Finally, we reannotated nine open reading frames in the mitochondrial genome that code for mitoribosomal proteins.https://elifesciences.org/articles/59264translationevolutioncryo-EMRNAgene expressionribosome |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Victor Tobiasson Alexey Amunts |
spellingShingle |
Victor Tobiasson Alexey Amunts Ciliate mitoribosome illuminates evolutionary steps of mitochondrial translation eLife translation evolution cryo-EM RNA gene expression ribosome |
author_facet |
Victor Tobiasson Alexey Amunts |
author_sort |
Victor Tobiasson |
title |
Ciliate mitoribosome illuminates evolutionary steps of mitochondrial translation |
title_short |
Ciliate mitoribosome illuminates evolutionary steps of mitochondrial translation |
title_full |
Ciliate mitoribosome illuminates evolutionary steps of mitochondrial translation |
title_fullStr |
Ciliate mitoribosome illuminates evolutionary steps of mitochondrial translation |
title_full_unstemmed |
Ciliate mitoribosome illuminates evolutionary steps of mitochondrial translation |
title_sort |
ciliate mitoribosome illuminates evolutionary steps of mitochondrial translation |
publisher |
eLife Sciences Publications Ltd |
series |
eLife |
issn |
2050-084X |
publishDate |
2020-06-01 |
description |
To understand the steps involved in the evolution of translation, we used Tetrahymena thermophila, a ciliate with high coding capacity of the mitochondrial genome, as the model organism and characterized its mitochondrial ribosome (mitoribosome) using cryo-EM. The structure of the mitoribosome reveals an assembly of 94-ribosomal proteins and four-rRNAs with an additional protein mass of ~700 kDa on the small subunit, while the large subunit lacks 5S rRNA. The structure also shows that the small subunit head is constrained, tRNA binding sites are formed by mitochondria-specific protein elements, conserved protein bS1 is excluded, and bacterial RNA polymerase binding site is blocked. We provide evidence for anintrinsic protein targeting system through visualization of mitochondria-specific mL105 by the exit tunnel that would facilitate the recruitment of a nascent polypeptide. Functional protein uS3m is encoded by three complementary genes from the nucleus and mitochondrion, establishing a link between genetic drift and mitochondrial translation. Finally, we reannotated nine open reading frames in the mitochondrial genome that code for mitoribosomal proteins. |
topic |
translation evolution cryo-EM RNA gene expression ribosome |
url |
https://elifesciences.org/articles/59264 |
work_keys_str_mv |
AT victortobiasson ciliatemitoribosomeilluminatesevolutionarystepsofmitochondrialtranslation AT alexeyamunts ciliatemitoribosomeilluminatesevolutionarystepsofmitochondrialtranslation |
_version_ |
1721458294832234496 |