Dr. Flavia Fontanesi publishes in NAR

Flavia Fontanesi directed the work of  Jeffri-Noelle Mays and led a three-lab collaborative effort that resulted in the publication on a paper in Nucleic Acids Research.

The paper, entitled “The mitoribosome-specific protein mS38 is preferentially required for synthesis of cytochrome c oxidase subunits” can be found at https://academic.oup.com/nar/advance-article/doi/10.1093/nar/gkz266/5436776

Authors: Jeffri-Noelle Mays, Yolanda Camacho-Villasana, Rodolfo Garcia-Villegas, Xochitl Perez-Martinez, Antoni Barrientos and Flavia Fontanesi

Abstract: Message-specific translational regulation mechanisms shape the biogenesis of multimeric oxidative phosphorylation (OXPHOS) enzyme in mitochondria from the yeast Saccharomyces cerevisiae. These mechanisms, driven mainly by the action of mRNA-specific translational activators, help to coordinate synthesis of OXPHOS catalytic subunits by the mitoribosomes with both the import of their nucleus-encoded partners and their assembly to form the holocomplexes. However, little is known regarding the role that the mitoribosome itself may play in mRNA-specific translational regulation. Here, we show that the mitoribosome small subunit protein Cox24/mS38, known to be necessary for mitoribosome-specific intersubunit bridge formation and 15S rRNA H44 stabilization, is required for efficient mitoribogenesis. Consequently, mS38 is necessary to sustain the overall mitochondrial protein synthesis rate, despite an adaptive ∼2-fold increase in mitoribosome abundance in mS38-deleted cells. Additionally, the absence of mS38 preferentially disturbs translation initiation of COX1, COX2, and COX3 mRNAs, without affecting the levels of mRNA-specific translational activators. We propose that mS38 confers the mitochondrial ribosome an intrinsic capacity of translational regulation, probably acquired during evolution from bacterial ribosomes to facilitate the translation of mitochondrial mRNAs, which lack typical anti-Shine-Dalgarno sequences.