Ten copies of the UAS regulatory sequence drive expression of the chimeric receptor which consists of robo1 in which the Ig1-Ig2 region has been replaced with the equivalent region of robo2. The protein is tagged at the N-terminal end with three copies of the Tag:HA tag. 5'UTR and signal sequences from the wg gene are also present.
Expression of robo1::robo2R2I1+2.10xScer\UAS.T:Ivir\HA1,T:SS-wg under the control of Scer\GAL4sli.PS in embryos results in ectopic crossing of the midline by Fas2-positive axons.