A pathway for mitotic chromosome formation
Program in Systems Biology; Department of Biochemistry and Molecular Pharmacology
Biochemistry | Computational Biology | Molecular Biology | Structural Biology | Systems Biology
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.
DOI of Published Version
Science. 2018 Feb 9;359(6376). pii: eaao6135. doi: 10.1126/science.aao6135. Epub 2018 Jan 18. Link to article on publisher's site
Science (New York, N.Y.)
Gibcus JH, Samejima K, Goloborodko A, Samejima I, Naumova N, Nuebler J, Kanemaki MT, Xie L, Paulson JR, Earnshaw WC, Mirny LA, Dekker J. (2018). A pathway for mitotic chromosome formation. Program in Systems Biology Publications. https://doi.org/10.1126/science.aao6135. Retrieved from https://escholarship.umassmed.edu/sysbio_pubs/118