mCSF1, a nucleus-encoded CRM protein required for the processing of many mitochondrial introns, is involved in the biogenesis of respiratory complexes I and IV in Arabidopsis

Authors

  • Michal Zmudjak,

    1. Institute of Plant Sciences, Agricultural Research Organization (ARO), Volcani Center, Bet Dagan, Israel
    2. Department of Plant Sciences, The Hebrew University of Jerusalem, Rehovot, Israel
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  • Catherine Colas des Francs-Small,

    1. Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, WA, Australia
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  • Ido Keren,

    1. Center for Plant Science Innovation, University of Nebraska, Lincoln, USA
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  • Felix Shaya,

    1. Institute of Plant Sciences, Agricultural Research Organization (ARO), Volcani Center, Bet Dagan, Israel
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  • Eduard Belausov,

    1. Institute of Plant Sciences, Agricultural Research Organization (ARO), Volcani Center, Bet Dagan, Israel
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  • Ian Small,

    1. Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, WA, Australia
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  • Oren Ostersetzer-Biran

    Corresponding authorCurrent affiliation:
    1. Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, Givat Ram, Hebrew University of Jerusalem, Jerusalem, Israel
    • Institute of Plant Sciences, Agricultural Research Organization (ARO), Volcani Center, Bet Dagan, Israel
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Author for correspondence:

Oren Ostersetzer-Biran

Tel: +972 3 968 3397

Email: biranos@volcani.agri.gov.il

Summary

  • The coding regions of many mitochondrial genes in plants are interrupted by intervening sequences that are classified as group II introns. Their splicing is essential for the expression of the genes they interrupt and hence for respiratory function, and is facilitated by various protein cofactors. Despite the importance of these cofactors, only a few of them have been characterized.
  • CRS1-YhbY domain (CRM) is a recently recognized RNA-binding domain that is present in several characterized splicing factors in plant chloroplasts. The Arabidopsis genome encodes 16 CRM proteins, but these are largely uncharacterized.
  • Here, we analyzed the intracellular location of one of these hypothetical proteins in Arabidopsis, mitochondrial CAF-like splicing factor 1 (mCSF1; At4 g31010), and analyzed the growth phenotypes and organellar activities associated with mcsf1 mutants in plants.
  • Our data indicated that mCSF1 resides within mitochondria and its functions are essential during embryogenesis. Mutant plants with reduced mCSF1 displayed inhibited germination and retarded growth phenotypes that were tightly associated with reduced complex I and IV activities. Analogously to the functions of plastid-localized CRM proteins, analysis of the RNA profiles in wildtype and mcsf1 plants showed that mCSF1 acts in the splicing of many of the group II intron RNAs in Arabidopsis mitochondria.

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