bims-mitran Biomed News
on Mitochondrial translation
Issue of 2025–05–25
two papers selected by
Andreas Kohler, Umeå University
  1. Silencing mitochondrial gene expression in living cells.
  2. Modelling POLG mutations in mice unravels a critical role of POLγΒ in regulating phenotypic severity.
  1. Science. 2025 May 22. eadr3498
    Silencing mitochondrial gene expression in living cells.
    Luis Daniel Cruz-Zaragoza, Drishan Dahal, Mats Koschel, Angela Boshnakovska, Aiturgan Zheenbekova, Mehmet Yilmaz, Marcel Morgenstern, Jan-Niklas Dohrke, Julian Bender, Anusha Valpadashi, Kristine A Henningfeld, Silke Oeljeklaus, Laura Sophie Kremer, Mirjam Breuer, Oliver Urbach, Sven Dennerlein, Michael Lidschreiber, Stefan Jakobs, Bettina Warscheid, Peter Rehling.
      Mitochondria fulfill central functions in metabolism and energy supply. They express their own genome, which encodes key subunits of the oxidative phosphorylation system. However, central mechanisms underlying mitochondrial gene expression remain enigmatic. A lack of suitable technologies to target mitochondrial protein synthesis in cells has limited experimental access. Here, we silenced the translation of specific mitochondrial mRNAs in living human cells by delivering synthetic peptide-morpholino chimeras. This approach allowed us to perform a comprehensive temporal monitoring of cellular responses. Our study provides insights into mitochondrial translation, its integration into cellular physiology, and provides a strategy to address mitochondrial gene expression in living cells. The approach can potentially be used to analyze mechanisms and pathophysiology of mitochondrial gene expression in a range of cellular model systems.
    DOI:  https://doi.org/10.1126/science.adr3498
  2. Nat Commun. 2025 May 23. 16(1): 4782
    Modelling POLG mutations in mice unravels a critical role of POLγΒ in regulating phenotypic severity.
    Samantha Corrà, Alessandro Zuppardo, Sebastian Valenzuela, Louise Jenninger, Raffaele Cerutti, Sirelin Sillamaa, Emily Hoberg, Katarina A S Johansson, Urska Rovsnik, Sara Volta, Pedro Silva-Pinheiro, Hannah Davis, Aleksandra Trifunovic, Michal Minczuk, Claes M Gustafsson, Anu Suomalainen, Massimo Zeviani, Bertil Macao, Xuefeng Zhu, Maria Falkenberg, Carlo Viscomi.
      DNA polymerase γ (POLγ), responsible for mitochondrial DNA replication, consists of a catalytic POLγA subunit and two accessory POLγB subunits. Mutations in POLG, which encodes POLγA, lead to various mitochondrial diseases. We investigated the most common POLG mutations (A467T, W748S, G848S, Y955C) by characterizing human and mouse POLγ variants. Our data reveal that these mutations significantly impair POLγ activities, with mouse variants exhibiting milder defects. Cryogenic electron microscopy highlighted structural differences between human and mouse POLγ, particularly in the POLγB subunit, which may explain the higher activity of mouse POLγ and the reduced severity of mutations in mice. We further generated a panel of mouse models mirroring common human POLG mutations, providing crucial insights into the pathogenesis of POLG-related disorders and establishing robust models for therapeutic development. Our findings emphasize the importance of POLγB in modulating the severity of POLG mutations.
    DOI:  https://doi.org/10.1038/s41467-025-60059-y
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