Fig. 1. glide and glide2 are expressed in tendon cells. (A,B) glide (A) and glide2 (B) in-situ hybridisation on wild-type Drosophila embryos, lateral views at mid-late stage 12. Unless specified, anterior is to the left in this and following figures. Both genes are expressed in epidermis (black arrows) and in glial cells of the central and peripheral nervous systems (large and small white arrowheads, respectively). Note that glide2 is expressed at lower levels compared with glide. (C-E) Anti-GFP (C) and anti-Stripe (D) immunolabelling on stage 14 glide::GFP embryos. Dorso-lateral views. GFP is expressed in epidermal cells (yellow brackets in C), peripheral glia (arrowheads in C) and hemocytes (asterisks in C), which also express glide and glide2 (Alfonso and Jones, 2002; Bernardoni et al., 1997; Kammerer and Giangrande, 2001). Tendon cells are visualised by anti-Stripe, those that are parallel to segment border cells being shown by empty lozenges (D). At this stage, intrasegmental tendon cells are organised in two clusters containing ten cells each and found at the dorsal and ventral ends of lateral transverse muscles (bracket in D indicates the dorsal cluster). (E) Merge labelling shows that epidermal glide-expressing cells at the segment border also express stripe (yellow nuclei in yellow brackets). Arrows in (D) indicate non-specific, tracheal, labelling. (F-H) Schematic representations of muscles and tendon cells in two abdominal segments of a Drosophila embryo at stage 16/17, lateral views, dorsal to the top (modified from Armand et al., 1994). Dotted and dashed lines represent dorsal and ventral midlines, respectively. Muscles are represented in white or red, tendon cells in green (segment border cells), yellow (parallel to segment border cells) or blue (intrasegmental tendon cells). Red muscles in (F,G) indicate longitudinal and ventral longitudinal muscles, respectively. Red muscles in H show lateral transverse muscles. Both ends of most longitudinal muscles (F,G) attach to segment borders, whereas a small subset displays only one attachment site at the border. Lateral transverse muscles (H) attach to intrasegmental tendon cells. The subpopulation of glide/glide2-expressing cells corresponds to green tendon cells. Black bracket in F indicates the region shown in C-E. Scale bars: 50 µm.