BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Changes in local chromatin structure during homology search: effec
 ts of local contacts on search time - Assaf Amitai (Massachusetts Institut
 e of Technology)
DTSTART:20160624T100000Z
DTEND:20160624T104500Z
UID:TALK66570@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:<span>Co-authors: Andrew Seeber (Friedrich Miescher Institute 
  for Biomedical Research)\, Susan M. Gasser (Friedrich Miescher Institute 
  for Biomedical Research)\, David Holcman (Ecole Normale Sup&eacute\;rieur
 e)  <br></span> <span><br>Double-strand break (DSB) repair by homologous r
 ecombination (HR) requires an  efficient and timely search for a homologou
 s template. Here we developed a  statistical method of analysis based on s
 ingle-particle trajectory data which  allows us to extract forces acting o
 n chromatin at DSBs. We can differentiate  between extrinsic forces from t
 he actin cytoskeleton and intrinsic alterations  on the nucleosomal level 
 at the cleaved MAT locus in budding yeast. Using  polymer models we show t
 hat reduced tethering forces lead to local  decondensation near DSBs\, whi
 ch reduces the mean first encounter time by two  orders of magnitude. Loca
 l decondensation\, likely stems from loss of internal  mechanical constrai
 nts and a local redistribution of nucleosomes that depends on  chromatin r
 emodelers. Simulations verify that local changes in inter-nucleosomal  con
 tacts near DSBs would shorten drastically the time required for a long-ran
 ge  homology search.</span>
LOCATION:Seminar Room 1\, Newton Institute
END:VEVENT
END:VCALENDAR