Capulet and Slingshot share overlapping functions during Drosophila eye morphogenesis

Area of Science:

• Cell Biology
• Developmental Biology
• Genetics

Background:

• Capulet (Capt), Slingshot (Ssh), and Twinstar (Tsr) are actin-binding proteins regulating actin polymerization.
• Previous studies indicated varied effects of loss-of-function mutations and RNAi depletions of these proteins on F-actin accumulation and cell morphology.
• The precise functional overlap of Capt, Ssh, and Tsr in specific tissues remained unclear.

Purpose of the Study:

• To investigate and compare the loss-of-function phenotypes of Capt, Ssh, and Tsr at single-cell resolution in Drosophila eye imaginal discs.
• To elucidate the specific cellular defects and molecular mechanisms underlying the loss of these actin-binding proteins.

Main Methods:

• Utilized MARCM or EGUF systems for generating loss-of-function mutant clones in Drosophila eye imaginal discs.
• Performed immunostaining and Fluorescence Recovery After Photobleaching (FRAP) on cultured eye discs.
• Analyzed phenotypes at single-cell resolution within the eye imaginal disc epithelium.

Main Results:

• Loss of Capt and Ssh, but not Tsr, resulted in similar cellular phenotypes in the Drosophila eye imaginal disc.
• Capt/Ssh mutant cells exhibited hexagonal packing with discontinuous adherens junctions.
• These cells showed complementary accumulation of phosphorylated myosin light chain (p-MLC) and F-actin rings at the apical cortex.
• Phenotypes were dependent on protein kinase A (PKA) inactivation and Rho activation.

Conclusions:

• Capt and Ssh share overlapping functions during eye morphogenesis, distinct from Tsr.
• These findings refine the understanding of actin regulation by Capt, Ssh, and Tsr in a developmental context.
• The study highlights the tissue-specific and context-dependent roles of these actin-binding proteins.