Lee JS, Kwak SJ, Kim J, Noh HM, Kim JS, Yu K. RNA-Guided Genome Editing in Drosophila with the Purified Cas9 Protein. G3 (Bethesda). 2014 May 28. pii: g3.114.012179. PMID: 24875628.
Abstract: "We report a method for generating Drosophila germline mutants effectively via injection of the complex of the purified Cas9 protein, tracrRNA, and gene-specific crRNAs, which may reduce delayed mutations because of the transient activity of the Cas9 protein, combined with the simple mutation detection in GO founders by the T7E1 assay."