A sequence cassette containing an Act5C:DsRed marker flanked by inverted attP sites has been inserted at cytological location 99F8. This cassette can be used as a target for recombination-mediated cassette exchange (RMCE); the entire attP-flanked cassette can be replaced with DNA from a compatible donor plasmid (where the sequence to be inserted is flanked by inverted attB sites) through RMCE driven by the phiC31:int integrase.