The BAF and PRC2 Complex Subunits Dpf2 and Eed Antagonistically Converge on Tbx3 to Control ESC Differentiation

Area of Science:

• Developmental Biology
• Epigenetics
• Stem Cell Biology

Background:

• BAF complexes regulate gene expression through chromatin remodeling.
• Specific BAF subunits have uncharacterized roles in embryonic stem cell (ESC) differentiation.
• Understanding subunit functions is key to deciphering developmental processes.

Purpose of the Study:

• To investigate the role of the Baf45 subunit Dpf2 in maintaining ESC pluripotency and differentiation.
• To elucidate the molecular mechanisms by which Dpf2 influences ESC fate decisions.
• To delineate the interplay between BAF and Polycomb Repressive Complex 2 (PRC2) in differentiation.

Main Methods:

• CRISPR-Cas9 mediated gene deletion of Dpf2 in ESCs.
• Chromatin immunoprecipitation sequencing (ChIP-seq) to assess protein occupancy at enhancers.
• Quantitative PCR and Western blotting to measure gene and protein expression levels.
• Assays for ESC self-renewal and differentiation potential.

Main Results:

• Dpf2 deletion in ESCs impairs self-renewal and mesendodermal differentiation.
• Dpf2 co-occupies enhancers with pluripotency factors (Oct4, Sox2) and Brg1.
• Dpf2 loss leads to Tbx3 repression, which can be rescued by Tbx3 re-expression.
• PRC2 subunits Eed and Ezh2 oppose Dpf2-mediated differentiation via Tbx3 and Nanog regulation, respectively.

Conclusions:

• Dpf2 is essential for maintaining ESC pluripotency and directing mesendodermal differentiation.
• Dpf2 regulates Tbx3 expression through epigenetic modifications at its enhancer.
• Distinct PRC2 subunits antagonize Dpf2's pro-differentiation roles through separate mechanisms.
• This study reveals specific functional contributions of BAF and PRC2 subunits in ESC differentiation.