Degenerate long-range interactions drive phase transition of heterochromatin [ChIP-Seq]

This is largely due to experimental challenges in targeted manipulation of the molecular components involved. We made use of C. elegans as elementary model system to unveil fundamental concepts of genome compartmentalization.

Simultaneous deletion of the H3 lysine 9 methylation-binding proteins HPL-2, a heterochromatin protein 1- type factor, and LIN-61, a malignant brain tudor-domain factor, expression of a dominant negative HPL-2 mutant, or abolishment of H3 lysine 9 methylation resulted in near-complete loss of A/B compartmentalization. Compartmentless genomes follow an equilibrium model of organization with transitions of compartment identity having only moderate effects on local contact domains or on gene expression.