基于反转录子的微生物基因编辑技术研究进展

Research progress in microbial gene editing based on retrons

摘要:

反转录子(retron)主要是由非编码RNA和逆转录酶所组成的参与抗噬菌体防御系统的细菌遗传元件。基于retron能产生多拷贝单链DNA的特性，将其与同源重组蛋白或CRISPR/Cas蛋白相结合已经在细菌和酵母中实现高效精准的基因编辑，而不依赖于外源DNA的直接引入。Retron系统经过不同优化，可应用于突变子文库构建、分子记录仪、蛋白连续进化等多个方向。本文首先介绍了retron的结构与分子机制，重点总结了基于retron的基因编辑技术在细菌和真菌中的应用，并对其优势和限制因素进行分析。最后对基于retron的基因编辑技术的未来发展进行了展望。

Abstract:

A retron, a bacterial genetic element mainly composed of a non-coding RNA and a reverse transcriptase, is involved in the anti-phage defense system. Since retrons can produce multi-copy single-stranded DNAs, combining retrons with proteins of homologous recombination or CRISPR/Cas has achieved efficient and accurate gene editing in bacteria and yeast, without relying on the direct introduction of exogenous DNAs. The optimized retron system can be applied in multiple fields such as mutant library construction, molecular recorder, and continuous evolution of proteins. This review introduces the structures and molecular mechanisms of retrons, summarizes the application of retron-based gene editing in bacteria and fungi, and analyzes the advantages and limitations of this technology. Finally, the future development of gene editing based on retrons is prospected.