Figure 7.

The clotting factor Lsp1γ accumulates at MASs. (A and B) Three hemisegments of the larval musculature stained for F-actin. (A) The normal pattern in WT larvae. (B) Ubiquitous induction of Lsp1γ RNAi reveal detached muscles (carets). (C) Quantitation of muscle attachment defects present in Lsp1γ knockdown larvae (16 ≤ n ≤ 40 for each genotype). Note that the penetrance is not increased in a fon-sensitized background. (D) Lsp1γ RNA is decreased upon RNAi knockdown as determined by qPCR. (E–H′) Lsp1γ–GFP fusion protein accumulates at sites consistent with tendon cell localization. (E–F′) The fusion protein is found at the ends of lateral muscles (small arrows in E, E′, and F) and on tendon cells at the segmental borders (arrowheads in E and E′). (G–H′) An XY (G and G′) or XZ (H and H′) scan through the plane shown in G reveals Lsp1γ accumulation on tendon cells (arrows), but not between adjacent muscles (open arrowhead). (I) Confirmation of tendon cell localization at segmental borders as visualized by GFP under control of the sr tendon cell promoter. Mean ± SD; P-values: **** P < 0.001, *** P < 0.005, n.s. = not significant. Bars, 150 µm for A and B; 50 µm for D–F and H.