BEGIN:VCALENDAR VERSION:2.0 PRODID:-//chikkutakku.com//RDFCal 1.0//EN X-WR-CALDESC:GoogleカレンダーやiCalendar形式情報を共有シェ アしましょう。近所のイベントから全国のイベントま で今日のイベント検索やスケジュールを決めるならち っくたっく X-WR-CALNAME:ちっくたっく X-WR-TIMEZONE:UTC BEGIN:VEVENT SUMMARY:CSB Special Lecture: Jan-Michael Peters\, Oct. 23\, 10 AM\, Munzer ! DTSTART;VALUE=DATE-TIME:20251023T170000Z DTEND;VALUE=DATE-TIME:20251023T180000Z UID:581940791289 DESCRIPTION:The Department of Chemical and Systems Biology PresentsSpecial  SeminarJan-Michael Peters\, PhDScientific Director\, Research Institute of Molecular Pathology (IMP)\, Vienna - BiocenterThursday\, October 23\, 2 02510:0 AM – 11:00 AM Munzer Auditorium Talk Title: "How cohesin folds the genome by loop extrusion"Abstract: Cohesin complexes fold genomic DNA by loop extrusion. The chromatin loops formed by this process have import ant functions in gene regulation\, recombination\, and DNA damage repair\, and defects in cohesin-mediated loop extrusion are thought to contribute to tumorigenesis and congenital ‘cohesinopathies’. ‘Structural maint enance of chromosomes’ (SMC) complexes related to cohesin exist in all k ingdoms of life and fold genomic DNA also in eubacteria and archaebacteria . Loop extrusion is therefore an ancient and fundamental process that migh t have facilitated the evolution of large DNA genomes.Using biochemical re constitution and single-molecule imaging\, we showed that cohesin extrudes DNA into cis-loops (Davidson\, Science 2019). This was an unexpected find ing since cohesin had initially been discovered for its ability to connect replicated DNA molecules in trans and had been proposed to mediate this s ister chromatid cohesion as a passive linker. Our work revealed that the c ohesin regulator NIPBL is a processivity factor for loop extrusion and not \, as initially proposed\, a cohesin loader. We provided direct evidence t hat CTCF is a directional boundary for cohesin-mediated loop extrusion (Da vidson\, Nature 2023) and found that cohesin is a unidirectional extruder that can switch the direction of extrusion when NIPBL unbinds and rebinds (Barth\, Cell 2025).We identified DNA binding sites and large-scale confor mational changes in cohesin and NIPBL that are required for loop extrusion \, showed that these are coordinated with cohesin’s ATP binding-hydrolys is cycle (Bauer\, Cell 2021) and found that cohesin takes large steps of 1 00-200 bp during loop extrusion (Davidson\, Nature 2023). We further obser ved that cohesin negatively supercoils DNA during loop extrusion and found that topoisomerase I is required for the formation of long cohesin loops in cells (Davidson\, Cell Rep. 2025).The length and lifetime of loops form ed by cohesin (‘cohesin loops’) is limited by WAPL\, which can release cohesin from chromatin (Kueng\, Cell 2006\; Tedeschi\, Nature 2013\; Wutz \, EMBO J.\, 2017\; see also Haarhuis\, Cell 2017)\, whereas the position of cohesin loops in the genome is determined by boundary elements\, such a s CTCF (Wendt\, Nature 2008\; Busslinger\, Nature 2017\; Wutz\, EMBO J.\, 2017\; see also Nora\, Cell 2017). We had found earlier that PDS5 proteins are also required for CTCF boundaries (Wutz\, EMBO J.\, 2017). We now dis covered that PDS5 proteins contribute to this function by facilitating the dissociation of NIPBL from cohesin\, thus limiting the lifetime of these complexes (Wutz\, bioRxiv 2025). LOCATION:Munzer Auditorium END:VEVENT END:VCALENDAR