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Elasticité de la chromatine, étude avec une pince optique

Abstract : This thesis is registered in the research context of the mechanical properties of the chromatin fibre and their role. After recalling the main knowledge on chromatin, we introduce the principal techniques for the manipulation of single molecule in the field of biophysics. We then expose our experimental setup we have developed and although the additional technique we have built more recently which enable the micro-manipulation with a rotative magnetic field.
Then we discuss our results on the DNA B-S transition: we suppose different behaviours of the DNA under tension according to the composition in base pair of a part of the DNA sequence (rich in C-G or not).
We present the results of the stretching on three main type of chromatin: force to disrupt a nucleosome and length of DNA released. We demonstrate that the nucleosome is not stable under the classical conditions of single molecule experiment: when the sample is too diluted.
We have confirmed these results with dilution experiments followed up of gel electrophoresis analysis. To understand our results established on stable chromatin fibres, we develop an already existing model. We try to gain information on the unwinding nucleosome under stretching for a better comprehension of the genetic regulation at the scale of the nucleofilament.
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Contributor : Cyrille Claudet <>
Submitted on : Thursday, October 26, 2006 - 10:56:13 AM
Last modification on : Tuesday, September 11, 2018 - 11:00:02 AM
Long-term archiving on: : Tuesday, April 6, 2010 - 6:28:49 PM


  • HAL Id : tel-00109955, version 1




Cyrille Claudet. Elasticité de la chromatine, étude avec une pince optique. Biophysique []. Université Joseph-Fourier - Grenoble I, 2005. Français. ⟨tel-00109955⟩



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