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, intronless sequence encoding the open reading frame of robo3 (starting at residue H21 and ending at the stop codon) and 2177bp of the robo1 3' flanking region (nucleotides 2R:18582049..18579873 , release 5 genome).