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UID:0-1125@lptms.universite-paris-saclay.fr
DTSTART;TZID=Europe/Paris:20260529T140000
DTEND;TZID=Europe/Paris:20260529T150000
DTSTAMP:20260428T142437Z
URL:https://www.lptms.universite-paris-saclay.fr/seminars/lptms-seminar-dm
 itry-starkov-skoltech-moscow/
SUMMARY:LPTMS Seminar: Dmitry Starkov (Skoltech\, Moscow) - Salle des sémi
 naires du FAST et du LPTMS\, bâtiment Pascal n°530 - 29 Mai 26 14:00
DESCRIPTION:Short-scale analytical theory shows cohesin actively extrudes l
 oops as a single motor\nDmitry Starkov (Skoltech\, Moscow)\n&nbsp\;\n\nCoh
 esin-dependent loop extrusion is a key active mechanism of DNA organizatio
 n\, yet it remains unclear whether chromatin loops in living cells are gen
 erated primarily by individual cohesin motors or by higher-order structure
 s. To fill this major gap\, we build an analytical\, protocol-aware polyme
 r-physics model that extracts a missing parameter - the linear density of 
 loops - directly from Hi-C data. We focus on short genomic distances\, whe
 re contact statistics simplify and chromatin can be described as an ideal 
 polymer folded by quenched disorder of cohesin-mediated loops. In this reg
 ime\, the Hi-C signal is governed by the interplay between loop-induced po
 lymer compaction and a finite-resolution contact-detection process\, which
  can be described by an effective Gaussian detection kernel. This results 
 in a perturbative expression for the contact probability of a looped chain
  under a finite contact-detection radius. Our theory recapitulates a chara
 cteristic dip in the logarithmic derivative of the contact probability tha
 t is broadly observed in experiments. By fitting this minimal model to a d
 iverse range of mammalian Hi-C datasets\, we infer approximately six loops
  per megabase. Independent imaging and mass spectrometry measurements of c
 ohesin density are consistent with our inferred loop density\, supporting 
 the monomeric mode of cohesin-mediated DNA loop extrusion.
CATEGORIES:seminars
LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53
 0\, rue André Riviere\, Orsay\, 91405\, France
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\
 , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST 
 et du LPTMS\, bâtiment Pascal n°530:geo:0,0
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DTSTART:20260329T030000
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