SCON—a Short Conditional intrON for conditional knockout with one-step zygote injection

The generation of conditional alleles using CRISPR technology is still challenging. Here, we introduce a Short Conditional intrON (SCON, 189 bp) that enables the rapid generation of conditional alleles via one-step zygote injection. In this study, a total of 13 SCON mouse lines were successfully generated by 2 different laboratories. SCON has conditional intronic functions in various vertebrate species, and its target insertion is as simple as CRISPR/Cas9-mediated gene tagging. Intronic Genetics: Crisp control to switch off genes In a procedure applicable to many different genes, the celebrated gene-editing technology known as CRISPR can insert a drug-controlled intronic ‘off switch’ into selected genes in mice via one-step zygote injections, allowing fine-tuned investigation of gene function. A research team led by Szu-Hsien Sam Wu and Bon-Kyoung Koo developed the procedure to generate intron-based conditional knock-out alleles. Here, the genetic modification is achieved using CRISPR gene-editing to insert a Short Conditional intrON called SCON (189 bp) into exons of genes. The authors successfully inserted SCON into 13 different genes. SCON is well tolerated in vivo when inserted into essential genes and fully compatible with the available recombinase lines for controlled switching off the gene when and where desired. SCON also shows potential application to other vertebrate species where zygote injection is feasible.