Smaruj Paulina, Kieliszek Marek
Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, United States of America.
College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, 02-097 Warsaw, Poland.
EXCLI J. 2023 Jan 5;22:70-83. doi: 10.17179/excli2022-5581. eCollection 2023.
Many archaeal and bacterial organisms possess an adaptive immunity system known as CRISPR-Cas. Its role is to recognize and degrade foreign DNA showing high similarity to repeats within the CRISPR array. In recent years computational techniques have been used to identify genes that are not associated with CRISPR systems, named . Often, genes are present in a conserved neighborhood of PolB-like polymerase genes, which is a characteristic feature of self-synthesizing, eukaryotic transposons of the Polinton class. Nearly all - genomic islands are flanked by terminal inverted repeats and direct repeats which correspond to target site duplications. Considering the patchy taxonomic distribution of the identified islands in archaeal and bacterial genomes, they were characterized as a new superfamily of mobile genetic elements and called casposons. Here, we review recent experiments on casposons' mobility and discuss their discovery, classification, and evolutionary relationship with the CRISPR-Cas systems.
许多古细菌和细菌生物体拥有一种名为CRISPR-Cas的适应性免疫系统。其作用是识别并降解与CRISPR阵列中的重复序列高度相似的外来DNA。近年来，计算技术已被用于识别与CRISPR系统无关的基因，称为 。通常， 基因存在于PolB样聚合酶基因的保守邻域中，这是Polinton类自我合成的真核转座子的一个特征。几乎所有的 - 基因组岛都由末端反向重复序列和对应于靶位点重复的正向重复序列侧翼包围。考虑到在古细菌和细菌基因组中已识别岛的零散分类分布，它们被表征为一个新的可移动遗传元件超家族，并称为转座子。在这里，我们回顾了最近关于转座子移动性的实验，并讨论了它们的发现、分类以及与CRISPR-Cas系统的进化关系。
