RT Journal Article
SR Electronic
T1 A quantitative map of human Condensins provides new insights into mitotic chromosome architecture
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 237834
DO 10.1101/237834
A1 Nike Walther
A1 M. Julius Hossain
A1 Antonio Z. Politi
A1 Birgit Koch
A1 Moritz Kueblbeck
A1 Øyvind Ødegård-Fougner
A1 Marko Lampe
A1 Jan Ellenberg
YR 2018
UL http://biorxiv.org/content/early/2018/01/09/237834.abstract
AB The two Condensin complexes in human cells are essential for mitotic chromosome structure. We used homozygous genome editing to fluorescently tag Condensin I and II subunits and mapped their absolute abundance, spacing and dynamic localization during mitosis by fluorescence correlation spectroscopy-calibrated live cell imaging and superresolution microscopy. While ~35,000 Condensin II complexes are stably bound to chromosomes throughout mitosis, ~195,000 Condensin I complexes dynamically bind in two steps, in prometaphase and early anaphase. The two Condensins rarely co-localize at the chromatid axis, where Condensin II is centrally confined but Condensin I reaches ~50% of the chromatid diameter from its center. Based on our comprehensive quantitative data, we propose a three-step hierarchical loop model of mitotic chromosome compaction: Condensin II initially fixes ~450 kb average sized loops at the chromatid axis whose size is then reduced by Condensin I binding to ~90 kb in prometaphase and ~70 kb in anaphase, achieving maximum chromosome compaction upon sister chromatid segregation.ABantibodyAPDavalanche photodiodeFCSfluorescence correlation spectroscopyFWHMfull width at half maximumGaAsPGallium arsenide phosphideHKHeLa KyotoINinputIPimmunoprecipitation / eluateNEBDnuclear envelope breakdownNocnocodazoleONovernightPOIprotein of interestROIregion of interestSBSouthern BlotSMCstructural maintenance of chromosomesSNsupernatantSTEDstimulated emission depletionWBWestern BlotZFNzinc finger nuclease