UAS regulatory sequences drive expression of four sgRNAs; two target fz (sgRNA sequences ATGTGGCAGTCCATCTAGTTCGG and GGCATAATGGTCATGTTATATGG) and two target fz3 (sgRNA sequences ATTGGTGTGACCTGCCAGGTTGG and CATAATGGCCCGGTGGCATCCGG). The sgRNAs are expressed as a single polycistronic tRNA-gRNA cassette.