Single-cell chromatin profiling reveals dynamic regulatory logic and enhancer elements in brain and retina development

Cell type identity in the nervous system is encoded within cis-regulatory landscapes that integrate transcription factor activity with chromatin accessibility. However, how these regulatory programs are organized and remodeled during post-embryonic neural development is poorly understood. We generate a temporally resolved single-cell chromatin accessibility atlas of ∼95,000 zebrafish brain and retina nuclei spanning larval, juvenile, and adult stages. We define 212 discrete chromatin states and uncover widespread, cell type-specific chromatin reorganization across development. By integrating with transcriptomic data, we link motif accessibility to transcription factor expression and identify regulatory programs that are either maintained or reconfigured during post-embryonic development of each neural cell type. Leveraging this atlas, we systematically identify and functionally validate candidate enhancers in vivo. Focusing on the <i>slc1a3b</i> locus in radial glia, we define evolutionarily conserved, compact enhancer modules that act combinatorially to drive gene expression. Together, these findings provide a systems-level framework for decoding neural regulatory logic and enable functional dissection of conserved cis-regulatory programs in the vertebrate nervous system.