CRISPR genome engineering allows the introduction of targeted genome alterations with unprecedented ease and precision. We have been among the first groups to adopt the CRISPR/Cas system for genome engineering in the model organism Drosophila melanogaster. Our approach has focused on the use of transgenic CRISPR components, which mediate targeted mutagenesis with remarkably high efficiency. At the heart of our system are transgenic cas9 fly lines expressing the RNA-guided endonuclease Cas9 under ubiquitous or germline specific promoters or linked to the Gal4/UAS system for expression in any tissue. These are complemented with optimised sgRNA expression vectors containing different U6 or UAS promoters or tRNA-sgRNA arrays. Plasmids encoding target specific gRNAs can be injected into cas9 embryos or integrated into the genome and crossed to cas9 strains. By choosing appropriate tools it is possible to generate loss-of-function mutations in essential or non-essential genes in a germline restricted, ubiquitous or tissue-specific fashion. It is also possible to introduce designer mutations by homology directed repair, ranging from single nucleotide changes to GFP knock-ins.
The idea behind the creation of this website was to establish a platform to facilitate the dissemination of our CRISPR tools. We launched CRISPRflydesign in August 2013, shortly after starting to send our transgenic Cas9 lines to interested labs. The website allows us to rapidly describe unpublished materials, provide step-by step protocols and to discuss additional aspects of gene editing that are not found in our formal publications. Most of our tools are also described in formal publications, which you can find here. All papers have been initially posted as preprints. We share our plasmids via Addgene and transgenic fly lines are available form the Vienna Drosophila Resource Center or the Bloomington Drosophila Stock Center.