Zhaoyu Xue, Menghua Wu, Kejia Wen, Menda Ren, Li Long, Xuedi Zhang and Guanjun Gao. CRISPR/Cas9 Mediates Efficient Conditional Mutagenesis in Drosophila. G3. Available as early online content.
From the abstract: "... tissue-specific expression of Cas9 driven by the Gal4/upstream activating site (UAS) system with various ubiquitously expressed gRNA transgenes to effectively inactivate gene expression in a temporally and spatially controlled manner. ... by including multiple gRNAs in a transgenic vector to target a single gene, we achieved a high degree of gene mutagenesis in specific tissues. ..."