VGN6341-Gal4 targeted knockdown of PlexA and Sema1a in a small subset of leg motoneurons. (A, C, E, G, I, K) innervation of proximal femur. (B, D, F, H, J, L) innervation of tibia. (A, B) Control innervation by targeted motoneurons. (C, D) Sema1a knockdown in targeted motoneurons. (E, F) PlexA knockdown in targeted motoneurons. (G, H) Sema1aP2 homozygous mutant. (I, J) Sema1aP1/Sema1aP2 heteroallelic combination. (K, L) Sema1ap2/+;;PlexA09/+ trans-heterozygous mutant combination. Decreased innervation occurs in femur (C, E, G, I, K) and ectopic innervation occurs in tibia (D, F, H, J, L). Arrowheads point toward innervation and asterisk denote absence of normal innervation. Scale bars = 20 microns.