Neurog1 and Neurog2 couple non-IT fate specification with cross-lineage cortical regionalization and bias recruitment into active circuits

While combinatorial transcription factor (TF) activity is thought to drive this diversification, evidence from single-cell transcriptomics remains largely correlative. Here, by integrating single-cell transcriptomic data mining with double-knockout and split-Cre lineage-specific ablation in mice, we show that co-expression of the proneural TFs Neurog1 and Neurog2 is enriched in, and required to specify, non-intratelencephalic (non-IT) neuronal fates.

Lineage tracing further reveals transient Neurog1/Neurog2 expression in intratelencephalic (IT) neurons, inhibitory interneurons, and astrocyte lineages, not specified by these TFs. Consistent with broader regulatory functions, integrative gene regulatory network analysis, single-cell meta-analysis, and spatial transcriptomics identify a Neurog1/Neurog2-co-regulated gene program delineating cortical regional identity. Additionally, lineage-labeled IT neurons show enrichment for immediate-early gene expression, with ~40% co-expressing Fos, suggesting activity-biased recruitment.