Intercellular signalling in Drosophila segment formation reconstructed in vitro

Area of Science:

• Developmental Biology
• Genetics
• Cell Signaling

Background:

• Intercellular signaling is vital for Drosophila melanogaster development.
• Previous research suggested involvement of multiple signaling pathways in segment polarity.
• The wingless (wg) gene product is a secreted glycoprotein similar to mouse Wnt-1.

Purpose of the Study:

• To investigate intercellular signaling in simplified in vitro systems.
• To test the model that wg protein acts as an extracellular signal maintaining engrailed (en) expression.
• To validate key predictions regarding wg signaling in cell culture.

Main Methods:

• Analysis of engrailed (en) and wingless (wg) gene expression in Drosophila embryos.
• Conditional mutagenesis to inactivate wg function.
• Isolation of purified embryonic cells using whole animal cell sorting.
• In vitro culture of en-expressing and wg-expressing cells.

Main Results:

• wg-deficient embryos show loss of en expression.
• Purified en-expressing cells lose en expression in culture.
• Purified wg-expressing cells provide a local signal that maintains en expression.
• Engineered heterologous cells expressing wg also exhibit signaling activity.

Conclusions:

• The wingless (wg) protein functions as a locally active extracellular signal.
• wg signaling is essential for maintaining engrailed (en) expression in Drosophila development.
• In vitro systems with purified cells can effectively study intercellular signaling pathways.