Nucleic Acids Research
Mitochondrial ribosomes synthesize essential components of the oxidative phosphorylation (OXPHOS) system in a tightly regulated process. In the yeast Saccharomyces cerevisiae, mitochondrial mRNAs require specific translational activators, which orchestrate protein synthesis by recognition of their target gene's 5'-untranslated region (UTR). Most of these yeast genes lack orthologues in mammals, and only one such gene-specific translational activator has been proposed in humans-TACO1. The mechanism by which TACO1 acts is unclear because mammalian mitochondrial mRNAs do not have significant 5'-UTRs, and therefore must promote translation by alternative mechanisms. In this study, we examined the role of the TACO1 orthologue in yeast. We found this 29 kDa protein to be a general mitochondrial translation factor, Dpc29, rather than a COX1-specific translational activator. Its activity was necessary for the optimal expression of OXPHOS mtDNA reporters, and mutations within the mitoribosomal large subunit protein gene MRP7 produced a global reduction of mitochondrial translation in dpc29Δ cells, indicative of a general mitochondrial translation factor. Northern-based mitoribosome profiling of dpc29Δ cells showed higher footprint frequencies at the 3' ends of mRNAs, suggesting a role in translation post-initiation. Additionally, human TACO1 expressed at native levels rescued defects in dpc29Δ yeast strains, suggesting that the two proteins perform highly conserved functions.
Hubble, Kyle A. and Henry, Michael F., "DPC29 Promotes Post-Initiation Mitochondrial Translation in Saccharomyces cerevisiae" (2023). Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship. 172.
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Kyle A Hubble , Michael F Henry, DPC29 promotes post-initiation mitochondrial translation in Saccharomyces cerevisiae, Nucleic Acids Research, Volume 51, Issue 3, 22 February 2023, Pages 1260–1276, https://doi.org/10.1093/nar/gkac1229