Functional analysis of the integrator subunit 12 identifies a microdomain that mediates activation of the drosophila integrator complex

Background: Small nuclear RNA (snRNA) 3′ end processing is carried out by the poorly understood integrator complex. Results: An essential microdomain within IntS12 binds IntS1 and is required for integrator complex activity. Conclusion: A small binding interface between the largest and smallest integrator subunits is critical for snRNA processing. Significance: These data uncover the unexpected findings that the IntS12 PHD finger is nearly dispensable for snRNA processing, whereas a microdomain is required.