Decapentaplegic and growth control in the developing Drosophila wing

Area of Science:

• Developmental Biology
• Genetics
• Molecular Biology

Background:

• Decapentaplegic (Dpp) is a key morphogen in Drosophila wing disc development, forming gradients to direct growth and pattern.
• The precise role of Dpp gradients in uniform cell proliferation versus pattern formation remains debated.

Purpose of the Study:

• To elucidate the spatiotemporal requirements of Dpp signaling in Drosophila wing disc development.
• To investigate the direct role of Dpp in cell proliferation and pattern formation.

Main Methods:

• CRISPR-Cas9 genome editing to create a conditional null allele for Dpp.
• Genetic removal of Dpp from its endogenous stripe domain in the anterior-posterior boundary.
• Analysis of downstream signaling (p-Mad) and target gene expression (sal, omb, brk).

Main Results:

• Dpp removal confirmed its role in activating the phospho-Mothers against dpp (p-Mad) gradient and regulating patterning genes.
• Wing discs lacking Dpp expression in the stripe domain showed normal proliferation rates and only mild growth defects.
• These findings challenge the direct requirement of the Dpp gradient for wing disc growth in late larval stages.

Conclusions:

• The Dpp gradient from the anterior-posterior boundary is essential for patterning but not directly for wing disc growth in the third larval instar.
• Dpp's primary function in late larval development is pattern formation, with growth regulation being indirectly influenced.