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An unexpectedly complex mitoribosome in Andalucia godoyi, a protist with the most bacteria-like mitochondrial genome.

Abstract：

:The mitoribosome, as known from studies in model organisms, deviates considerably from its ancestor, the bacterial ribosome. Deviations include substantial reduction of the mitochondrial ribosomal RNA (mt-rRNA) structure and acquisition of numerous mitochondrion-specific (M) mitoribosomal proteins (mtRPs). A broadly accepted view assumes that M-mtRPs compensate for structural destabilization of mt-rRNA resulting from its evolutionary remodeling. Since most experimental information on mitoribosome makeup comes from eukaryotes having derived mitochondrial genomes and mt-rRNAs, we tested this assumption by investigating the mitochondrial translation machinery of jakobids, a lineage of unicellular protists with the most bacteria-like mitochondrial genomes. We report here proteomics analyses of the Andalucia godoyi small mitoribosomal subunit and in silico transcriptomic and comparative genome analyses of four additional jakobids. Jakobids have mt-rRNA structures that minimally differ from their bacterial counterparts. Yet, with at least 31 small subunit (SSU) and 44 large subunit (LSU) mtRPs, the mitoriboproteome of Andalucia is essentially as complex as that in animals or fungi. Further, the relatively high conservation of jakobid sequences has helped to clarify the identity of several mtRPs, previously considered to be lineage-specific, as divergent homologs of conserved M-mtRPs, notably mS22 and mL61. The coexistence of bacteria-like mt-rRNAs and a complex mitoriboproteome refutes the view that M-mtRPs were ancestrally recruited to stabilize deviations of mt-rRNA structural elements. We postulate instead that the numerous M-mtRPs acquired in the last eukaryotic common ancestor allowed mt-rRNAs to pursue a broad range of evolutionary trajectories across lineages: from dramatic reduction to acquisition of novel elements to structural conservatism.

journal_name

Mol Biol Evol

journal_title

Molecular biology and evolution

authors

Valach M,Alcazar JAG,Sarrasin M,Lang BF,Gray MW,Burger G

doi

10.1093/molbev/msaa223

subject

Has Abstract

pub_date

2020-09-04 00:00:00

eissn

0737-4038

issn

1537-1719

pii

5901548

pub_type

杂志文章

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An unexpectedly complex mitoribosome in Andalucia godoyi, a protist with the most bacteria-like mitochondrial genome.