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Role of the fission yeast SUMO E3 ligase Pli1p in centromere and telomere maintenance

Blerta Xhemalce, Jacob‐S Seeler, Geneviève Thon, Anne Dejean, Benoît Arcangioli

Author Affiliations

  1. Blerta Xhemalce*,1,3,
  2. Jacob‐S Seeler2,3,
  3. Geneviève Thon3,
  4. Anne Dejean2 and
  5. Benoît Arcangioli*,1
  1. 1 Unité de la Dynamique du Génome, Institut Pasteur, Paris Cedex, France
  2. 2 Unité Organisation Nucléaire et Oncogénèse, Institut Pasteur, Paris Cedex, France
  3. 3 Department of Genetics, Institute of Molecular Biology, University of Copenhagen, Copenhagen K, Denmark
  1. *Corresponding authors. Unité de la Dynamique du Génome, URA1664 du CNRS, Jacques Monod Building, Institut Pasteur, 25, rue du Dr Roux, 75724, Paris Cedex 15, France. Tel.: +33 1 4568 8454; Fax: +33 1 4568 8960; E-mail: blerta{at}pasteur.fr or E-mail: barcan{at}pasteur.fr
  1. These authors contributed equally to this work

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Abstract

Sumoylation represents a conserved mechanism of post‐translational protein modification. We report that Pli1p, the unique fission yeast member of the SP‐RING family, is a SUMO E3 ligase in vivo and in vitro. pli1Δ cells display no obvious mitotic growth defects, but are sensitive to the microtubule‐destabilizing drug TBZ and exhibit enhanced minichromosome loss. The weakened centromeric function of pli1Δ cells may be related to the defective heterochromatin structure at the central core, as shown by the reduced silencing of an ura4 variegation reporter gene inserted at cnt and imr. Interestingly, pli1Δ cells also exhibit enhanced loss of the ura4 reporter at these loci, likely by gene conversion using homologous sequences as information donors. Moreover, pli1Δ cells exhibit consistent telomere length increase, possibly achieved by a similar process. Point mutations within the RING finger of Pli1p totally or partially reproduce the pli1 deletion phenotypes, thus correlating with their sumoylation activity. Altogether, these results strongly suggest that Pli1p, and by extension sumoylation, is involved in mechanisms that regulate recombination in particular heterochromatic repeated sequences.

  • Received March 29, 2004.
  • Accepted August 12, 2004.
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