GATA4 Regulates Developing Endocardium Through Interaction With ETS1

Area of Science:

• Cardiovascular Biology
• Developmental Biology
• Epigenetics

Background:

• GATA4 (GATA Binding Protein 4) is a crucial transcription factor for heart development, with lineage-specific roles.
• Understanding GATA4's occupancy and regulatory mechanisms in different heart cell types is essential.

Purpose of the Study:

• To characterize GATA4 chromatin occupancy in cardiomyocyte and endocardial lineages.
• To dissect mechanisms controlling lineage-specific GATA4 binding.
• To analyze GATA4's regulation of endocardial gene expression.

Main Methods:

• Mapped GATA4 chromatin occupancy using lineage-specific biotinylation in embryonic mouse hearts.
• Studied GATA4 pioneering activity regulation in cell lines.
• Analyzed GATA4's role in endocardial gene expression via single-cell RNA sequencing and reporter assays.

Main Results:

• GATA4 occupied regions in cardiomyocytes and endocardial cells acted as lineage-specific enhancers.
• NKX2-5 and ETS1 motifs were enriched in these regions, and both interacted with GATA4.
• ETS1 more potently redirected GATA4 binding and chromatin opening than NKX2-5, linking ETS1 to endocardial development.

Conclusions:

• Lineage-specific transcription factors NKX2-5 and ETS1 guide pioneer transcription factor GATA4 binding.
• These interactions open chromatin and create active enhancers.
• ETS1 interaction with GATA4 mechanistically links to endocardial development.