AtnMat2, a nuclear-encoded maturase required for splicing of group-II introns in Arabidopsis mitochondria

  1. Ido Keren1,2,4,
  2. Ayenachew Bezawork-Geleta1,4,5,
  3. Max Kolton1,
  4. Inbar Maayan1,
  5. Eduard Belausov1,
  6. Maggie Levy3,
  7. Anahit Mett1,
  8. David Gidoni1,
  9. Felix Shaya1 and
  10. Oren Ostersetzer-Biran1
  1. 1Volcani Center, Institute of Plant Sciences, Agricultural Research Organization, Bet Dagan 50250, Israel
  2. 2Department of Plant Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
  3. 3Department of Plant Pathology and Microbiology, The Hebrew University of Jerusalem, Rehovot 76100, Israel
    • 5 Present address: Department of Biochemistry, La Trobe University, Melbourne 3086, Australia.

    1. 4 These authors contributed equally to this work.

    Abstract

    Mitochondria (mt) in plants house about 20 group-II introns, which lie within protein-coding genes required in both organellar genome expression and respiration activities. While in nonplant systems the splicing of group-II introns is mediated by proteins encoded within the introns themselves (known as “maturases”), only a single maturase ORF (matR) has retained in the mitochondrial genomes in plants; however, its putative role(s) in the splicing of organellar introns is yet to be established. Clues to other proteins are scarce, but these are likely encoded within the nucleus as there are no obvious candidates among the remaining ORFs within the mtDNA. Intriguingly, higher plants genomes contain four maturase-related genes, which exist in the nucleus as self-standing ORFs, out of the context of their evolutionary-related group-II introns “hosts.” These are all predicted to reside within mitochondria and may therefore act “in-trans” in the splicing of organellar-encoded introns. Here, we analyzed the intracellular locations of the four nuclear-encoded maturases in Arabidopsis and established the roles of one of these genes, At5g46920 (AtnMat2), in the splicing of several mitochondrial introns, including the single intron within cox2, nad1 intron2, and nad7 intron2.

    Keywords:

    Keywords

    Footnotes

    • Reprint requests to: Oren Ostersetzer-Biran, Volcani Center, Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan 50250, Israel; e-mail: biranos{at}volcani.agri.gov.il; fax: +972-3-966-9583

    • Article and publication date are at http://www.rnajournal.org/cgi/doi/10.1261/rna.1776409.

      • Received June 15, 2009.
      • Accepted September 15, 2009.
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