BMP-mediated induction of GATA4/5/6 blocks somitic responsiveness to SHH

Area of Science:

• Developmental Biology
• Molecular Biology
• Cell Signaling

Background:

• The differentiation of presomitic mesoderm (PSM) into specific cell types is regulated by the interplay of Sonic hedgehog (SHH) and bone morphogenetic protein (BMP) signaling pathways.
• Understanding the molecular mechanisms governing cell fate decisions in early embryonic development is crucial for regenerative medicine and developmental studies.

Purpose of the Study:

• To elucidate the regulatory roles of Nkx3.2 and GATA transcription factors in the context of SHH and BMP signaling during mesoderm differentiation.
• To investigate the interaction between GATA factors, Gli factors, and the co-factor FOG1 in modulating hedgehog signaling.

Main Methods:

• Chick PSM explant cultures
• Gene expression analysis
• Protein-protein interaction studies
• Gene knockdown experiments

Main Results:

• SHH-induced Nkx3.2 maintains chondrogenic competence by repressing BMP-dependent GATA gene induction.
• BMP signaling or GATA factor expression inhibits hedgehog-dependent gene expression in PSM.
• GATA factors, with FOG1, repress SHH-induced Gli1 expression by binding to regulatory regions.
• FOG1 knockdown abrogates GATA-mediated repression of Gli1.

Conclusions:

• GATA transcription factors act as novel repressors of hedgehog signaling.
• Nkx3.2 plays a key role in maintaining sclerotomal cell potential by suppressing GATA induction under BMP influence.
• This study reveals a complex regulatory network governing mesoderm fate decisions through cross-talk between SHH, BMP, Nkx3.2, and GATA pathways.