Excision of the FRT-w cassette from progenitor AxnΔRGS.Arm.FRT.αTub84B.Tag:FLAG allows the αTub84B promoter to drive expression of an Axn deletion mutant lacking the RGS and Arm domains (R53-I172 and E462-S538, respectively) which is fused with N-terminal 6xTag:FLAG.