title: The yeast model suggests the use of short peptides derived from mt LeuRS for the therapy of diseases due to mutations in several mt tRNAs.
abstract: We have previously established a yeast model of mitochondrial (mt) diseases. We showed that defective respiratory phenotypes due to point-mutations in mt tRNA(Leu(UUR)), tRNA(Ile) and tRNA(Val) could be relieved by overexpression of both cognate and non-cognate nuclearly encoded mt aminoacyl-tRNA synthetases (aaRS) LeuRS, IleRS and ValRS. More recently, we showed that the isolated carboxy-terminal domain (Cterm) of yeast mt LeuRS, and even short peptides derived from the human Cterm, have the same suppressing abilities as the whole enzymes. In this work, we extend these results by investigating the activity of a number of mt aaRS from either class I or II towards a panel of mt tRNAs. The Cterm of both human and yeast mt LeuRS has the same spectrum of activity as mt aaRS belonging to class I and subclass a, which is the most extensive among the whole enzymes. Yeast Cterm is demonstrated to be endowed with mt targeting activity. Importantly, peptide fragments β30_31 and β32_33, derived from the human Cterm, have even higher efficiency as well as wider spectrum of activity, thus opening new avenues for therapeutic intervention. Bind-shifting experiments show that the β30_31 peptide directly interacts with human mt tRNA(Leu(UUR)) and tRNA(Ile), suggesting that the rescuing activity of isolated peptide fragments is mediated by a chaperone-like mechanism. Wide-range suppression appears to be idiosyncratic of LeuRS and its fragments, since it is not shared by Cterminal regions derived from human mt IleRS or ValRS, which are expected to have very different structures and interactions with tRNAs.
authors.affiliation: Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy.
authors.forename: Patrizio
authors.initials: P
authors.lastname: Di Micco
authors.affiliation: Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Fazzi D'Orsi
authors.affiliation: National Research Council of Italy (CNR) - Institute of Biology, Molecular Medicine and Nanobiotechnology (IBMN), Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy.
authors.forename: Veronica
authors.initials: V
authors.lastname: Morea
authors.affiliation: Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy; Pasteur Institute - Cenci Bolognetti Foundation, Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Frontali
authors.affiliation: Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy; Pasteur Institute - Cenci Bolognetti Foundation, Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Francisci
authors.affiliation: Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy. Electronic address: ari.montanari@uniroma1.it.
authors.forename: Arianna
authors.initials: A
authors.lastname: Montanari
keywords: Aminoacyl tRNA synthetases; C-term domain; Mitochondrial diseases; Mitochondrial tRNA mutations; Suppressive sequences