Dynamique et régulation des assemblages nucléoprotéiques des télomères humains : Fonctions de la protéine TRF2.

Abstract : TRF2 is a key protein in the dynamic of telomere, these regions at the end of linear chromosomes that protect and stabilize chromosome ends. Telomeres can fold into t-loops that were proposed to result from the invasion of the 3' overhang of telomeres into duplex DNA. Their formation is facilitated in vitro by the telomeric protein TRF2, but very little is known regarding the mechanisms involved. We reveal that TRF2 generates positive supercoiling and condenses DNA. Using a variety of TRF2 mutants, we demonstrated a strong correlation between this topological activity and the ability to stimulate strand invasion. We propose that TRF2 complexes, by wrapping DNA around themselves in a right-handed manner induce untwisting of the neighboring DNA, thereby favoring strand invasion. In addition, we demonstrate that the N-terminal domain of TRF2 is a second DNA binding domain which posesses a strong affinity a the Holliday Junction structure. The last part of this thesis reports the identification of the 5' exonuclease activity of Apollo, a new telomeric protein involved in telomeric protection. The results presented give fresh insight in new TRF2 functions that have many implications in telomere biology and in particular the role of TRF2 in t-loop formation.
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https://tel.archives-ouvertes.fr/tel-00534812
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Submitted on : Wednesday, November 10, 2010 - 3:25:00 PM
Last modification on : Friday, November 9, 2018 - 11:20:03 AM
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  • HAL Id : tel-00534812, version 1

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Simon Amiard. Dynamique et régulation des assemblages nucléoprotéiques des télomères humains : Fonctions de la protéine TRF2.. Sciences du Vivant [q-bio]. Université d'Orléans, 2007. Français. ⟨tel-00534812⟩

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