Contains 2386bp of the robo1 5' flanking region (coordinates 2R:18589619..18587234 , release 5 genome), which includes the region encoding the robo1 signal peptide up to residue Q52, 4 tandem Tag:HA tags, a fusion protein with the N-terminal part derived from robo1 (up to and including residue Y1028) and the C-terminal part derived from robo3 (starting from residue G1028) and 2177bp of the robo1 3' flanking region (nucleotides 2R:18582049..18579873 , release 5 genome).