Handles on chromosome architecture

Cohesin organizes genome folding through loop extrusion, a process regulated by cofactors including NIPBL and PDS5. Recent studies by Wutz et al. and Shah et al. demonstrate that NIPBL promotes loop expansion in mammalian cells, whereas PDS5 restricts loop growth by facilitating NIPBL dissociation from cohesin. Together, these findings reveal a finely tuned mechanism governing genome folding.