Insertion sequence transposition activates antimycobacteriophage immunity through an Isr2-silenced lipid metabolism gene island  

作　　者：Yakun Li Yuyun Wei Xiao Guo Xiaohui Li Lining Lu Lihua Hu Zheng-Guo He 

机构地区：[1]State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources,Guangxi Research Center for Microbial and Enzyme Engineering Technology,College of Life Scienceand Technology,Guangxi University,Nanning,China

出　　处：《mLife》2024年第1期87-100,共14页微生物（英文）

基　　金：supported by the National Natural Science Foundation of China(32230002);the National Key R&D Program of China(2020YFA0907200),and the Ba-Gui Scholar Program of Guangxi(To Z.G.H).

摘　　要：Insertion sequences(ISs)exist widely in bacterial genomes,but their roles in the evolution of bacterial antiphage defense remain to be clarified.Here,we report that,under the pressure of phage infection,the IS1o96 transposition of Mycobacterium smegmatis into the Isr2 gene can occur at high frequencies,which endows the mutant mycobacterium with a broad-spectrum antiphage ability.Lsr2 functions as a negative regulator and directly silences expression of a gene island composed of 11 lipid metabolism-related genes.The complete or partial loss of the gene island leads to a significant decrease of bacteriophage adsorption to the mycobacterium,thus defending against phage infection.Strikingly,a phage that has evolved mutations in two tail-filament genes can re-escape from the Isr2 inactivation-triggered host defense.This study uncovered a new signaling pathway for activating antimycobacteriophage immunity by Is transposition and provided insight into the natural evolution of bacterial antiphage defense.

关 键 词：antiphage defense BACTERIOPHAGE gene island insertion sequence MYCOBACTERIA 

分 类 号：Q93[生物学—微生物学]