Single-cell chromatin accessibility maps reveal regulatory programs driving early mouse organogenesis

Area of Science:

• Developmental Biology
• Genomics
• Epigenetics

Background:

• Understanding the regulatory programs governing early organogenesis is crucial for defining cell repertoires.
• Comprehensive chromatin landscapes during mammalian embryonic development are not well-defined.

Purpose of the Study:

• To delineate comprehensive chromatin landscapes during early organogenesis.
• To identify cell-type-specific regulatory elements and transcriptional regulators.

Main Methods:

• Single-nucleus chromatin accessibility mapping (ATAC-seq) of 19,453 cells from mouse embryos at 8.25 days post-fertilization.
• Identification and validation of cell-type-specific enhancers using transgenic mouse assays.
• Integration of gene expression data and transcription factor motif enrichment analysis.
• In vivo validation experiments in zebrafish.

Main Results:

• Mapped chromatin accessibility revealed cell-type-specific regulatory regions.
• Identified two TAL1-bound endothelial enhancers crucial for vascular development.
• Highlighted cell-type-specific transcriptional regulators, including the ETS factor FEV, essential for endothelial identity.

Conclusions:

• Single-cell chromatin accessibility maps provide insights into the regulatory blueprint of mammalian organogenesis.
• The study validates the role of specific enhancers and transcription factors in early development.
• Cross-species validation in zebrafish confirms conserved mechanisms in endothelial development.