Fig. 1. Localisation of talin N- and C-terminal domains in the embryo. (A-G) Confocal images of muscles from two segments of a late-stage Drosophila embryo. A,B are anti-talin stained fixed embryos and C-G are images of GFP fluorescence in live embryos. (A) Talin is enriched at integrin adhesion sites at muscle ends (arrowheads). (B) Elevating talin expression with mef2::Gal4 and UAS::talin resulted in a modest increase in localized talin and a larger increase in cytoplasmic talin. The mef2::Gal4 driver was also used to express the following domain fusion proteins. TalinH-GFP (C) was localized to muscle ends, but expression in the cytoplasm and nuclei was also observed. GFP-talinC (D) localized to muscle ends and the developing Z-lines. (E,F) Reduction in endogenous talin caused an increase in talinH-GFP recruitment to muscle ends and a loss of GFP-talinC. (G) Removal of PS2ßPS integrin caused the loss of talinH-GFP from the muscle ends. (H) TalinH-GFP, detected with an anti-GFP antibody, remained intact despite the putative calpain cleavage site between talinH and GFP. Arrow indicates where cleaved GFP would migrate. (I) An antibody raised against the talin head domain stains muscle attachments in wild-type embryos. (J) embryos expressing talinH-GFP also showed nuclear and cytoplasmic staining, identical to the GFP fluorescence from this fusion protein (C). Bar, 20 µm.