The pCFD4 vector is designed for expression of two guide RNA (gRNA) sequences, with each sgRNA being expressed individually under the control of a ubiquitous promoter; the two promoters are U6:1 (snRNA:U6:96Aa) and U6:3 (snRNA:U6:96Ac). The vector contains an attB site, allowing integration into an attP-containing docking site in the genome to produce a transgenic construct.