Research Article

A pathway for mitotic chromosome formation

See allHide authors and affiliations

Science  18 Jan 2018:
eaao6135
DOI: 10.1126/science.aao6135

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution

Abstract

Mitotic chromosomes fold as compact arrays of chromatin loops. To identify the pathway of mitotic chromosome formation, we combined imaging and Hi-C of synchronous DT40 cell cultures with polymer simulations. We show that in prophase, the interphase organization is rapidly lost in a condensin-dependent manner and arrays of consecutive 60 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 during prometaphase to ~12 Mb. Acute depletion of condensin I or II shows that nested loops form by differential action of the two condensins while condensin II is required for helical winding.

View Full Text