Continuous cell type diversification throughout the embryonic and postnatal mouse visual cortex development.

Area of Science:

• Neuroscience
• Developmental Biology
• Genomics

Background:

• Mammalian cortical development involves diverse cell types and temporally regulated events.
• Mechanisms of cell type development are not fully understood.
• Single-cell transcriptomics enables systematic study of cell types during development.

Purpose of the Study:

• To create a high-resolution transcriptomic and epigenomic atlas of the developing mouse visual cortex.
• To map cell type emergence and diversification throughout development.
• To identify molecular signatures and regulatory mechanisms driving cell identity refinement.

Main Methods:

• Single-cell RNA sequencing (scRNA-seq) of 568,674 cells.
• Single-nucleus Multiome sequencing (snMultiome) of 194,545 nuclei for transcriptomic and chromatin accessibility.
• Computational reconstruction of developmental trajectories.
• Analysis of gene expression and chromatin accessibility dynamics.

Main Results:

• Comprehensive atlas of excitatory, inhibitory, and non-neuronal cell types from embryonic to postnatal stages (E11.5-P56).
• Identification of branching points for new cell type emergence and molecular signatures of diversification.
• Continuous cell type refinement observed postnatally, with late emergence during eye-opening and critical periods.
• Dynamic interplay between gene expression and chromatin accessibility, identifying regulatory elements and transcription factors.
• Demonstration that single genes can be regulated by multiple elements across cell types and developmental stages.

Conclusions:

• The study provides the most detailed dynamic molecular map of developing visual cortex cell types.
• It reveals the molecular logic underlying continuous cell type refinement.
• The findings offer insights into the complex processes governing cortical development and cell identity formation.