Nucleic Acids Research Advance Access originally published online on April 17, 2008
Nucleic Acids Research 2008 36(10):3244-3251; doi:10.1093/nar/gkn154
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Nucleic Acids Research, 2008, Vol. 36, No. 10 3244-3251
© 2008 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Molecular Biology |
Developmentally programmed DNA splicing in Paramecium reveals short-distance crosstalk between DNA cleavage sites
1Ecole Normale Supérieure, Laboratoire de Génétique Moléculaire, 46 rue d’Ulm, 75005 Paris, 2CNRS UMR 8541, 46 rue d’Ulm, 75005 Paris, 3CNRS UPR 2167, Centre de Génétique Moléculaire, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, 4Univ Paris-Sud, UFR de Sciences, F-91405 Orsay, 5Université Pierre et Marie Curie – Paris 6, Paris, UFR des Sciences de la Vie, F-75005 Paris and 6Université Paris Diderot – Paris 7, UFR des Sciences du Vivant, 75205 Paris cedex 13, France
*To whom correspondence should be addressed. Tel: +33 1 69 82 31 64; Fax: +33 1 69 82 31 81; Email: mireille.betermier{at}cgm.cnrs-gif.fr
Received February 1, 2008. Revised March 18, 2008. Accepted March 19, 2008.
Somatic genome assembly in the ciliate Paramecium involves the precise excision of thousands of short internal eliminated sequences (IESs) that are scattered throughout the germline genome and often interrupt open reading frames. Excision is initiated by double-strand breaks centered on the TA dinucleotides that are conserved at each IES boundary, but the factors that drive cleavage site recognition remain unknown. A degenerate consensus was identified previously at IES ends and genetic analyses confirmed the participation of their nucleotide sequence in efficient excision. Even for wild-type IESs, however, variant excision patterns (excised or nonexcised) may be inherited maternally through sexual events, in a homology-dependent manner. We show here that this maternal epigenetic control interferes with the targeting of DNA breaks at IES ends. Furthermore, we demonstrate that a mutation in the TA at one end of an IES impairs DNA cleavage not only at the mutant end but also at the wild-type end. We conclude that crosstalk between both ends takes place prior to their cleavage and propose that the ability of an IES to adopt an excision-prone conformation depends on the combination of its nucleotide sequence and of additional determinants.
Present addresses: Ariane Gratias, CNRS UMR 8618 - Institut de Biotechnologie des Plantes, Université Paris Sud Bât. 630. 91405 Orsay Cedex, France Gersende Lepère, Laboratoire de Biologie Cellulaire, INRA Centre de Versailles, 78026 Versailles Cedex, France