Hedgehog morphogen gradient is robust towards variations in tissue morphology in Drosophila

Area of Science:

• Developmental Biology
• Cell Signaling
• Biophysics

Background:

• Morphogens are crucial signaling molecules that guide tissue development by forming concentration gradients.
• Understanding how tissue morphology influences morphogen gradient formation is essential for developmental biology.
• Previous studies focused on morphogen spreading mechanisms but largely ignored the impact of tissue shape.

Purpose of the Study:

• To investigate whether tissue morphology affects the shape of morphogen gradients.
• To develop and apply a novel analysis pipeline for quantifying protein distribution in curved tissues.
• To assess the robustness of the Hedgehog (Hh) gradient in Drosophila imaginal discs with varying morphologies.

Main Methods:

• Developed a computational pipeline to quantify protein distribution within curved biological tissues.
• Applied the pipeline to analyze the Hedgehog morphogen gradient in Drosophila melanogaster wing (flat) and eye-antennal imaginal discs (curved).
• Experimentally manipulated tissue morphology in both wing and eye-antennal imaginal discs to assess gradient response.

Main Results:

• The slope of the Hedgehog gradient was comparable between flat and curved Drosophila imaginal discs, despite differences in expression profiles.
• Inducing ectopic folds in wing imaginal discs did not alter the Hedgehog gradient slope.
• Reducing curvature in eye-antennal imaginal discs maintained gradient slope but resulted in ectopic Hedgehog expression.

Conclusions:

• The developed analysis pipeline enables robust quantification of protein distribution in complex, curved tissues.
• Hedgehog morphogen gradients exhibit remarkable robustness to variations in tissue morphology during Drosophila development.
• Tissue shape does not appear to be a primary determinant of Hedgehog gradient slope, suggesting intrinsic regulatory mechanisms maintain gradient fidelity.