A 146bp portion of scro has been deleted (the deletion removes part of exon 3 and the 5' splice site of intron 3 and starts just downstream of the start codon in the exon), and replaced with a sequence cassette that contains the GAL4::p65 coding sequence followed by an SV40 transcription termination signal, and a Equa\eqFP578TagRFP.3xP3 marker. This is expected to disrupt all scro isoforms (as exon 3 is common to all isoforms) and to result in GAL4::p65 being expressed under the control of the endogenous scro regulatory sequences.