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UID:20250515T050708EDT-6016sGEAxa@132.216.98.100
DTSTAMP:20250515T090708Z
DESCRIPTION:'Mechanics\, topology and geometry of mammalian chromosomes and
  nuclei and their epigenetic modulation'\n\nJohn Marko\, Northwestern Univ
 ersity\n	Tuesday January 14\, 12-1pm\n	Montreal Neurological Institute\, deG
 randpre Communications Centre\n\nAbstract: I will discuss studies of the m
 echanics and structure of metaphase chromosomes and nuclei extracted from 
 mammalian cells using glass micropipettes. Using a combination of mechanic
 al\, biochemical and genetic approaches we have shown that the metaphase c
 hromosome is a 'chromatin gel'\, without a contiguous protein scaffold\, a
 nd via SMC2 siRNA experiments\, that condensin plays a major role as a 'cr
 osslinker'. I will also discuss the 'loop-extrusion' model for establishme
 nt of chromatid structure\, with special attention to how it generates com
 paction of chromosomes along their length\, or 'lengthwise compaction'\, a
 nd how this provides a mechanism for chromatid and chromosome individualiz
 ation. I will then describe use of the same general approach to analyze th
 e mechanics of mammalian G1 nuclei. The nucleus shows two distinct mechani
 cal responses: an initial chromatin-dominated elastic behavior\, followed 
 by a stiffer\, lamin-dominated regime at larger extension. The low-force c
 hromatin-based elasticity can be modulated by changing histone acetylation
  and methylation\, and the morphology of the nucleus is impacted by these 
 changes\, with heterochromatinization driving the nucleus to be stiffer an
 d rounder\, and with euchromatinization destabilizing nuclear shape.\n
DTSTART:20200114T170000Z
DTEND:20200114T180000Z
LOCATION:deGrandpre Communications Centre\, Montreal Neurological Institute
 \, CA\, QC\, Montreal\, H3A 2B4\, 3801 rue University
SUMMARY:QLS Seminar Series - John Marko
URL:/qls/channels/event/qls-seminar-series-john-marko-
 303509
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