插入序列共同区元件：细菌中新出现的一种基因捕获系统

摘要：插入序列共同区（Insertion sequence common region，ISCR）元件是一类在结构和功能上与IS91家族相似的特殊插入序列，特点是缺少了末端反向重复序列（Inverted repeats, IRs），在插入位点不产生直接重复序列，并通过滚环式（Rolling circle, RC）进行转座。ISCR元件作为一种新的基因捕获系统，它可以移动邻近的任何DNA序列，为耐药基因在不同种属细菌间水平传播提供了高效的媒介。世界各地多种革兰氏阴性病原菌中已发现有19种ISCR元件，大部分ISCR元件同时携带了多种耐药基因，提示ISCR有可能会造成细菌多重耐药性的快速传播。本文就ISCR结构特征、类型、移动方式、起源及进化的研究进展进行了综述。

Insertion sequence common region element: a novel gene-capturing system in bacteria-A review

Abstract: Insertion sequence common region (ISCR) elements are insertion sequences that have similarities to the IS91 family in both structure and function. ISCR elements differ from the insertion sequences by that they lack terminal inverted repeats (IRs), do not generate directly repeated sequence on insertion and are thought to be transposed by a mechanism termed rolling-circle (RC) transposition. ISCR elements, as a novel gene-capturing system, can mobilize any piece of adjacent DNA sequences. This powerful gene mobilization mechanism provides antibiotic resistance genes with a highly mobile genetic vehicle to transfer between different species of bacteria. Nineteen members of the ISCR family have been discovered until now in many Gram-negative pathogens. The majority of these elements are found to be closely associated with antimicrobial resistance genes that are not necessary components of the host genome, suggesting that ISCR elements may be responsible for the rapid transmission of bacterial multi-drug resistance. This review described some important aspects of ISCR elements, including their structure characteristics, classification, mobilization mechanism, origins and evolutions.