UASt regulates expression of the RA isoform of cmb in which the five phospho-acceptor Ser/Thr residues (plus an additional neighboring Thr residue) have been mutation to Ala. The coding sequence is tagged at the N-terminal end with 3xTag:FLAG.
cmb6A.UAS.RA.Tag:FLAG/Scer\GAL4VP16.bam fails to rescue cmbKO