P{U6:1-U6:2-U6:3-wg.gRNA.P1-3} contains three copies of a guide RNA (gRNA) which targets the wg promoter, each copy expressed under the control of one of the snRNA:U6:96Aa, snRNA:U6:96Ab and snRNA:U6:96Ac promoters.
Embryos carrying wggRNA.U6:1-U6:2-U6:3.P1-3 and Zzzz\Cas9Act5C.cPa arrest before the end of embryogenesis with a strong segment polarity phenotype.