Establishment of heterochromatin in domain-size-dependent bursts
Jan Fabio Nickels, Ashleigh Edwards, Sebastian Jespersen Charlton, Amanda Møller Mortensen, Sif Christine Lykke Hougaard, Ala Trusina, Kim Sneppen, Geneviève Thon
Abstract
Significance How repressive heterochromatic states propagate along chromosomes and are subsequently maintained for many cell divisions remain important unanswered questions in biology. Combining mathematical modeling and single-cell measurements, we find that heterochromatin does not propagate in a purely linear manner as often assumed. Rather, sudden transitions can affect large domains globally at once. We suggest this is due to long-range interactions that bring distant nucleosomes close to each other to facilitate their modification. This supports the notion that the compartmentalization of chromatin components within the nucleus and the folding of chromatin into loops dynamically control heterochromatin propagation in three dimensions by bringing nucleosomes and their modifiers into close proximity.