P-22

Use of E-cadherin-GFP fusion protein to study cell adhesion and migration during Drosophila oogenesis.

V.Verkhusha1, S.Tsukita1,2, H. Oda1

�i1: Tsukita Cell Axis Project, ERATO, JST, 2: Fac. of Medicine, Kyoto Univ.�j

Coordination of cell migration and adhesion is essential for concerted movement of tissues during animal morphogenesis. These events occur in Drosophila oogenesis when border cells break from the anterior post-mitotic follicular epithelium, acquire a mesenchymal-like morphology, and migrate posteriorly between nurse cells to the oocyte. It was shown recently that Drosophila E-cadherin (DE-cadherin) is highly expressed in somatic follicle cells and moderately in germ cells. To investigate its role in above mentioned processes we have constructed DE-cadherin-GFP (DE-GFP) fusion protein by direct linkage of mutated GFP (F64L, S65C, I167T) to the C-terminal cytoplasmic region of DE-cadherin. Targeted expression of DE-GFP in border cells and part of posterior follicle cells was driven by UAS/GAL4 system. DE-GFP has the same features as a native DE-cadherin: correctly localizes in the outer cell membrane, exhibits adhesive properties, accumulates in the lateral sides near to apical part of follicular epithelium visualizing the adherent junctions. GFP signal almost coincides with fluorescence resulting from staining by both Abs, anti-GFP or anti-DE-cadherin. DE-GFP visualize the tail region of migrating border cells providing a hypothesis that part of adhesive molecules is pulled out and left behind on the surface of nurse cells as the border cells detaches and moves forward. The forepart filopodia of moving border cells exhibit much lower GFP signal in comparison with Abs staining, probably, due to high speed turnover of adhesive molecules making insufficient the time for GFP chromophore formation. Now under way are culturing experiments of isolated egg chambers to study DE-GFP trafficking and border cells migration in dynamics.