Fairytale: A High-Throughput TAL Effector Synthesis Platform

Recombinant transcription activator-like effectors (TALEs) have been effectively used for genome editing and gene regulation applications. Due to their remarkable modularity, TALEs can be tailored to specifically target almost any user-defined DNA sequences. Here, we introduce fairyTALE, a liquid phase high-throughput Golden Gate TALE synthesis platform capable of producing TALE-nucleases, activators, and repressors that recognize DNA sequences between 14 and 31 bp. It features a highly efficient reaction scheme, a flexible functionalization platform, and fully automated robotic liquid handling that enable the production of hundreds of TALEs within a single day with over 98% assembly efficiency at a reagent cost of just $5 per TALE – from desired targets to expression-ready plasmids. As proof of concept, we synthesized and tested 90 TALEs, each recognizing 27 bp, without restrictions on their sequence composition. 96% of these TALEs were found to be functional, while sequencing confirmation revealed that the non-functional constructs were all correctly assembled. FairyTALE offers an unprecedented combination of efficiency, fidelity, speed, and cost. We believe it has the potential to revolutionize the use of TALEs for genome scale applications.