CTCF/RAD21 organize the ground state of chromatin-nuclear speckle association

Recent findings indicate that nuclear speckles, a distinct type of nuclear body, interact with certain chromatin regions in a ground state. Here, we report that the chromatin structural factors CTCF and cohesin are required for full ground-state association between DNA and nuclear speckles. We identified a putative speckle targeting motif (STM) within cohesin subunit RAD21 and demonstrated that the STM is required for chromatin-nuclear speckle association, disruption of which impaired induction of speckle-associated genes. Depletion of the cohesin-releasing factor WAPL, which stabilizes cohesin on chromatin and reinforces DNA–speckle contacts, results in enhanced inducibility of speckle-associated genes. Additionally, we observed disruption of chromatin–nuclear speckle association in patient-derived cells with Cornelia de Lange syndrome, a congenital neurodevelopmental disorder involving defective cohesin pathways. In summary, our findings reveal a mechanism for establishing the ground state of chromatin–speckle association and promoting gene inducibility, with relevance to human disease. Refer to specific sequencing types.