Summary Transcription activator-like effector nucleases (TALENs) are facile and potent tools used to modify a gene of interest for targeted gene knockout.TALENs consist of an N-terminal domain, a DNA-binding domain, and a C-terminal domain, which are derived from a transcription activator-like effector, and the non-specific nuclease domain of FokI.Using Xenopus Collections tropicalis (X.tropicalis), we compared the toxicities and somatic mutation activities of four TALEN architectures in a side-by-side manner: a basic TALEN, a scaffold with the same truncated N- and C-terminal domains as GoldyTALEN, a scaffold with the truncated N- and C-terminal domains and an obligate heterodimeric nuclease domain, and a scaffold with the truncated N- and C-terminal domains and an obligate heterodimeric Sharkey nuclease domain.The strongest phenotype and targeted somatic gene mutation were induced by the injection of TALEN mRNAs containing the truncated N- and C-terminal domains and an obligate heterodimeric nuclease domain.
The obligate heterodimeric TALENs exhibited reduced toxicity compared to the homodimeric TALENs, and the Art homodimeric GoldyTALEN-type scaffold showed both a high activity of somatic gene modification and high toxicity.The Sharkey mutation in the heterodimeric nuclease domain reduced the TALEN-mediated somatic mutagenesis.