The UAS-Mer-RNAi line described in Su et al., 2017, Dev. Cell 40(5): 478--490.e3 (FBrf0235878) was constructed according to the methods in Lee and Carthew (2003). A 418bp fragment from exon 2 of Merlin (91-508), obtained by PCR of LD04288, was cloned into pWIZ, both into the AvrII site downstream of the white intron and into the NheI site upstream of the white intron. The two fragments are in head-to-head orientation.