UAS regulatory sequences drive expression of four sgRNAs; two target Wnt2 (sgRNA sequences CGCTGGCCCGGGGTCAGGCCCGG and AATCTACATACTCTGGATTATGG) and two target Wnt5 (sgRNA sequences GCCAGTGGACCTGCGGGACTCGG and GCCAGCCAGTCTCACCGACGAGG). The sgRNAs are expressed as a single polycistronic tRNA-gRNA cassette.