Stat3/Cdc25a-dependent cell proliferation promotes embryonic axis extension during zebrafish gastrulation

Area of Science:

• Developmental Biology
• Genetics

Background:

• Cell proliferation was not considered essential for embryonic axis extension during vertebrate gastrulation.
• Signal transducer and activator of transcription 3 (Stat3) is a key regulator of cell proliferation, survival, and regeneration, implicated in human diseases like scoliosis and cancer.
• Zebrafish Stat3 was previously suggested to regulate gastrulation movements via Wnt/Planar Cell Polarity (PCP) signaling.

Purpose of the Study:

• To investigate the role of cell proliferation in anteroposterior embryonic axis extension during gastrulation.
• To elucidate the function of Zebrafish Stat3 in embryonic development and axis elongation.

Main Methods:

• Utilized zebrafish stat3 null mutants and pharmacological inhibitors.
• Assessed convergence movements, planar cell polarity signaling, cell proliferation, and apoptosis.
• Examined the expression of Cdc25a and its effect on gastrulation.

Main Results:

• Zebrafish embryos lacking Stat3 exhibited normal convergence and PCP signaling but had transient axis elongation defects due to reduced cell proliferation and increased apoptosis.
• Pharmacological inhibition of cell proliferation mimicked the axis elongation defects observed in stat3 mutants.
• Stat3 upregulates Cdc25a expression during oogenesis, which is crucial for cell proliferation and axis extension; restoring Cdc25a partially rescued defects in stat3 mutants.
• Stat3 mutant zebrafish displayed developmental issues including stunted growth, scoliosis, and inflammation.

Conclusions:

• Cell proliferation, regulated by Stat3, is critical for anteroposterior embryonic axis extension during gastrulation.
• Stat3 plays a vital role in vertebrate development, potentially serving as a genetic model for studying development, regeneration, and diseases linked to Stat3 dysfunction.