Cytosine base editors (CBEs) can install a predefined stop codon at the target site, representing a more predictable and neater method for creating genetic knockouts without altering the genome size. Due to the enhanced predictability of the editing outcomes, it is also more efficient to obtain homozygous mutants in the first generation. With the recent advancement of CBEs on improved editing activity, purify and specificity in plants and animals, base editing has become a more appealing technology for generating knockouts. However, there is a lack of design tools that can aid the adoption of CBEs for achieving such a purpose, especially in plants. Here, we developed a user-friendly design tool named CRISPR-BETS (base editing to stop), which helps with guide RNA (gRNA) design for introducing stop codons in the protein-coding genes of interest. We demonstrated in rice and tomato that CRISPR-BETS is easy-to-use, and its generated gRNAs are highly specific and efficient for generating stop codons and obtaining homozygous knockout lines. While we tailored the tool for the plant research community, CRISPR-BETS can also serve non-plant species.

中文翻译：

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CRISPR-BETS：一种用于生成终止密码子的碱基编辑设计工具


胞嘧啶碱基编辑器 (CBE) 可以在目标位点安装预定义的终止密码子，这是一种在不改变基因组大小的情况下创建基因敲除的更可预测和更简洁的方法。由于编辑结果的可预测性增强，在第一代获得纯合突变体的效率也更高。随着最近 CBE 在植物和动物中改善编辑活性、纯化和特异性方面取得的进展，碱基编辑已成为一种更有吸引力的基因敲除技术。然而，缺乏可以帮助采用 CBE 来实现这一目的的设计工具，尤其是在工厂中。在这里，我们开发了一种名为 CRISPR-BETS（碱基编辑终止）的用户友好型设计工具，它有助于指导 RNA (gRNA) 设计，以在感兴趣的蛋白质编码基因中引入终止密码子。我们在水稻和番茄中证明了 CRISPR-BETS 易于使用，其生成的 gRNA 具有高度特异性，可有效生成终止密码子并获得纯合敲除系。虽然我们为植物研究界定制了该工具，但 CRISPR-BETS 也可以为非植物物种服务。