Functional Conservation of Divergent p63-Bound cis-Regulatory Elements

Area of Science:

• Developmental Biology
• Evolutionary Biology
• Genetics

Background:

• The transcription factor p63 is crucial for vertebrate ectoderm development, regulating epidermis, limbs, and craniofacial tissues.
• Understanding the evolutionary conservation of p63's regulatory mechanisms provides insights into developmental processes.

Purpose of the Study:

• To investigate the evolutionary conservation of p63 binding sites (BSs) and the gene regulatory network (GRN) it orchestrates between zebrafish and humans.
• To functionally validate conserved p63 BSs using transgenic reporter assays.

Main Methods:

• Comparative analysis of ChIP-seq data for p63 BSs in human keratinocytes and zebrafish embryos.
• Comparison of p63-regulated gene networks between zebrafish and humans.
• Transgenic reporter assays in zebrafish embryos to test the function of human and zebrafish p63 BSs.

Main Results:

• Sequence conservation of p63 BSs between zebrafish and humans was found to be very poor.
• A high overlap was observed in the gene regulatory networks orchestrated by p63 in both species, indicating functional conservation.
• Transgenic reporter assays confirmed that both human and zebrafish p63 BSs can drive reporter expression in common tissues relevant to epidermal development.

Conclusions:

• The gene regulatory network controlled by p63 is highly conserved across vertebrates.
• Despite significant divergence in p63-bound regulatory elements (BSs), their function in orchestrating ectoderm development is maintained.