Figure 1.

Loss of robo1 reduces survival rate. (A) Structure of the fly robo1 gene and alleles. The CRIMIC T2A-miniGAL4 sequence is inserted into a shared intron of all robo1 transcripts, truncating the transcript and protein while expressing T2A-miniGAL4 (21). The nonsense robo1¹ (p.Q411Term) allele (2) as well as the chromosomal deficiency Df(2R)BSC787 allele are indicated. (B) Confocal images of Robo1 immunostaining in stage 16–17 embryos as well as 3rd instar larval (L3) brains of robo1^T2A-GAL4/+ and robo1^T2A-GAL4/robo1^T2A (left). Immunoblot of Robo1 extracted from L3 larval brains of robo1^T2A-GAL4/+ and robo1^T2A-GAL4/robo1^T2A. α-Tubulin served as a loading control (right). (C) Confocal images of FasII immunostaining in stage 16 embryo VNC. (D) Viability rates of adult robo1 mutants with different null alleles.