The Integrator complex prevents premature neuronal differentiation through global control of transcription elongation.

Transcription pause-release constitutes a key step in the regulation of gene expression. Pathogenic variants in various pausing regulators have been identified in neurodevelopmental disorders, but how transcription pause-release regulates neural development remains largely unknown. Here we show that a patient-specific in-frame deletion in Integrator subunit 8 (INTS8) that prevents association of this subunit with the Integrator complex results in a global increase in nascent transcription and precocious expression of neuronal genes in progenitor cells. Consequently, differentiating neural progenitors fail to sustain a proliferating progenitor cell population during cortical neuronal network formation, resulting in network collapse. We show that attenuation of RNApol2 pause-release by targeted degradation of BRD4 can revert neuronal gene activation and prevent premature progenitor cell loss. Our data demonstrate that a fine-tuned balance between RNApol2 pausing and elongation is crucial for normal neuronal development and suggest transcription pause-release as a druggable target for neurological defects in developmental disorders.