A snRNA:U6:96Ac promoter drives expression of four sgRNAs; two (TGGATCCGGATCGGAAACCG and GTACCAGGAGCAGAGCACCG) target Ptp52F for knockout, two (CTAAGCGTGGTGATTCCCTG and GTTAAGGGATAAAAGAAACG) target Ptp69D for knockout. The sgRNAs are expressed as a polycistronic cassette based on the tRNA-gRNA design of FBrf0233589.