Fig. 1.

Drosophila RacGAP mutants have defects in somatic muscle patterning. Stage 16 embryos stained for Muscle myosin. Muscle patterning is shown at low (A,B) and high (D-I) magnification in wild-type (wt) (A,D,F,H) or RacGAP50C^DH15 (B,E,G,I) embryos. (A) Muscle pattern as observed in the whole embryo. (B) No significant loss of muscle tissue or unfused myoblasts are observed in RacGAP50C^DH15 mutants. (D,E) Arrows in D mark normal attachments of DO1. In RacGAP50C^DH15, DO1 is in the incorrect position (E, arrows). (F,G) Arrowheads in F mark muscle 22 (LT2). Arrowheads in G mark an LT muscle of an abnormal shape. The arrow marks a rounded muscle that fails to migrate. (H,I) Arrowheads in H mark normal attachments for VO muscles. In RacGAP50C^DH15 mutants, these muscles fail to fully extend (I, arrowheads). (C) Schematic of the wild-type muscle pattern of a single abdominal hemisegment, showing the names and numbers for muscles as referred to throughout this work. DA, dorsal acute; DO, dorsal oblique; LT, lateral transverse; VL, ventral lateral; VO, ventral oblique.