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A pathway for mitotic chromosome formation.

ABSTRACT: Mitotic chromosomes fold as compact arrays of chromatin loops. To identify the pathway of mitotic chromosome formation, we combined imaging and Hi-C analysis of synchronous DT40 cell cultures with polymer simulations. Here we show that in prophase, the interphase organization is rapidly lost in a condensin-dependent manner, and arrays of consecutive 60-kilobase (kb) loops are formed. During prometaphase, ~80-kb inner loops are nested within ~400-kb outer loops. The loop array acquires a helical arrangement with consecutive loops emanating from a central "spiral staircase" condensin scaffold. The size of helical turns progressively increases to ~12 megabases during prometaphase. Acute depletion of condensin I or II shows that nested loops form by differential action of the two condensins, whereas condensin II is required for helical winding.

SUBMITTER: Gibcus JH

PROVIDER: S-EPMC5924687 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

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A pathway for mitotic chromosome formation.

Gibcus Johan H JH Samejima Kumiko K Goloborodko Anton A Samejima Itaru I Naumova Natalia N Nuebler Johannes J Kanemaki Masato T MT Xie Linfeng L Paulson James R JR Earnshaw William C WC Mirny Leonid A LA Dekker Job J

Science (New York, N.Y.) 20180118 6376

Mitotic chromosomes fold as compact arrays of chromatin loops. To identify the pathway of mitotic chromosome formation, we combined imaging and Hi-C analysis of synchronous DT40 cell cultures with polymer simulations. Here we show that in prophase, the interphase organization is rapidly lost in a condensin-dependent manner, and arrays of consecutive 60-kilobase (kb) loops are formed. During prometaphase, ~80-kb inner loops are nested within ~400-kb outer loops. The loop array acquires a helical ...[more]

PMID: 29348367

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