(A–F) 3D confocal micrographs of BCs. The UAS-gfp::act (green) transgene is driven by slboGal4, and MRLC::mCherry (red) serves as readout for contractile force exertion during migration. Nuclei are labeled by DAPI (blue), and anti-FasIII (magenta) is used to label polar cells (A and B). Rap1V12 overexpression gives rise to brush-like protrusions (yellow arrowheads) and multiple long protrusions (white arrows) in the hpo[42–47]/+ background (A–D). Lamellipodium-like membrane extension is also observed in scattered BCs (E and F).
(G and H) Time-lapse micrographs show actin protrusions (green, G) and MRLC-mCherry accumulation (red, H) in hpo[42–47]-hemizygous BCs expressing UAS-rap1V12.
(I) Quantification of protrusion number and cluster scattering in BCs with specific genotypes.
(J) Quantification of spreading areas of BC clusters.
*p < 0.05, ***p < 0.001. n is the total number of egg chambers examined. Scale bars, 50 μm in (A) and (E) and 20 μm in (B)–(D) and (F). The error bars represent SD.