Chromosomes Progress to Metaphase in Multiple Discrete Steps via Global Compaction/Expansion Cycles.

ABSTRACT: Mammalian mitotic chromosome morphogenesis was analyzed by 4D live-cell and snapshot deconvolution fluorescence imaging. Prophase chromosomes, whose organization was previously unknown, are revealed to comprise co-oriented sister linear loop arrays displayed along a single, peripheral, regularly kinked topoisomerase II/cohesin/condensin II axis. Thereafter, rather than smooth, progressive compaction as generally envisioned, progression to metaphase is a discontinuous process involving chromosome expansion as well as compaction. At late prophase, dependent on topoisomerase II and with concomitant cohesin release, chromosomes expand, axes split and straighten, and chromatin loops transit to a radial disposition around now-central axes. Finally, chromosomes globally compact, giving the metaph

SUBMITTER: Liang Z 

PROVIDER: S-EPMC4448932 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature