mRNA stability fine tunes gene expression in the developing cortex to control neurogenesis

RNA expression levels are controlled by the complementary processes of synthesis and degradation. Although mis-regulation of RNA turnover is linked to neurodevelopmental disorders, how it contributes to cortical development is largely unknown. Here, we profile the RNA stability landscape of the cortex across development and demonstrate that control of stability by the CCR4-NOT complex is essential for corticogenesis in vivo . First, we use SLAM-seq to measure RNA half-lives transcriptome-wide across multiple stages of cortical development. We characterize cis -acting features associated with RNA stability and find that RNAs that are upregulated across development tend to be more stable, while downregulated RNAs are less stable. To probe how disruption of RNA turnover impacts cortical development, we assess developmental requirements of CNOT3, a core component of the CCR4-NOT deadenylase complex. Mutations in CNOT3 are associated with human neurodevelopmental disorders, however its role in cortical development is unknown. Conditional knockout of Cnot3 in neural progenitors and their progeny in the developing mouse cortex leads to severe microcephaly due to reduced neuron production and p53-dependent apoptosis. Collectively, our findings demonstrate that fine-tuned control of RNA turnover is crucial for brain development.