对反式作用crRNA的分析揭示了V-K型CRISPR相关转座酶（CAST）系统的V2亚组。

Analysis of tracrRNAs reveals subgroup V2 of type V-K CAST systems.

作者信息

Ziemann Marcus, Mitrofanov Alexander, Stöckl Richard, Alkhnbashi Omer S, Backofen Rolf, Hess Wolfgang R

机构信息

Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, D-79104 Freiburg, Germany.

Department of Computer Science, Bioinformatics Group, University of Freiburg, D-79110 Freiburg, Germany.

出版信息

Microlife. 2025 Aug 21;6:uqaf020. doi: 10.1093/femsml/uqaf020. eCollection 2025.

DOI:10.1093/femsml/uqaf020

PMID:40927181

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC12416283/

Abstract

Clustered regularly interspaced palindromic repeats (CRISPR)-associated transposons (CAST) consist of an integration between certain class 1 or class 2 CRISPR-Cas systems and Tn7-like transposons. Class 2 type V-K CAST systems are restricted to cyanobacteria. Here, we identified a unique subgroup of type V-K systems through phylogenetic analysis, classified as V-K_V2. Subgroup V-K_V2 CAST systems are characterized by an alternative tracrRNA, the exclusive use of Arc_2-type transcriptional regulators, and distinct differences in the length of protein domains in TnsB and TnsC. Although the occurrence of V-K_V2 CAST systems is restricted to Nostocales cyanobacteria, it shows signs of horizontal gene transfer, indicating its capability for genetic mobility. The predicted V-K_V2 tracrRNA secondary structure has been integrated into an updated version of the CRISPRtracrRNA program available on GitHub under https://github.com/BackofenLab/CRISPRtracrRNA/releases/tag/2.0.

摘要

成簇规律间隔回文重复序列（CRISPR）相关转座子（CAST）由某些1类或2类CRISPR-Cas系统与Tn7样转座子之间的整合组成。2类V-K型CAST系统仅限于蓝细菌。在这里，我们通过系统发育分析鉴定了一个独特的V-K系统亚群，归类为V-K_V2。V-K_V2亚群CAST系统的特征是具有替代性反式激活crRNA，仅使用Arc_2型转录调节因子，以及TnsB和TnsC中蛋白质结构域长度的明显差异。尽管V-K_V2 CAST系统的出现仅限于念珠藻目蓝细菌，但它显示出水平基因转移的迹象，表明其具有遗传移动能力。预测的V-K_V2反式激活crRNA二级结构已整合到可在GitHub上获取的CRISPRtracrRNA程序的更新版本中，网址为https://github.com/BackofenLab/CRISPRtracrRNA/releases/tag/2.0。