AUTHOR=Lee Chanjae , Choo Kyungsil , Lee Sung-Jae 

TITLE=Active Transposition of Insertion Sequences by Oxidative Stress in Deinococcus geothermalis

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.558747

DOI=10.3389/fmicb.2020.558747

ISSN=1664-302X

ABSTRACT=<p>Radiation-resistant bacterium <italic>Deinococcus geothermalis</italic> has a total of 73 insertion sequences (ISs) in genomes, and some of them are actively transposed to other loci with replicative mode due to oxidative stress of hydrogen peroxide treatment. Here, we detected two transposition events in wild-type (WT) strain and LysR family member gene disrupted strain (Δ<italic>dgeo</italic>_2840). Similar to our previous report (<xref ref-type="bibr" rid="B21">Lee et al., 2019</xref>), phytoene desaturase (<italic>dgeo</italic>_0524), a key enzyme of carotenoid biosynthesis, was disrupted by the integration of IS element, thereby detected a single phenotypically non-pigmented colony in each WT and Δ<italic>dgeo</italic>_2840 strain. Two separate types of IS element have been integrated into non-pigmented clones: IS<italic>Dge11</italic> for WT and IS<italic>Dge6</italic> for Δ<italic>dgeo</italic>_2840 strain. Surprisingly, Δ<italic>dgeo</italic>_2840 mutant strain revealed higher resistance to oxidative stress than WT strain at late exponential growth phase. From the qRT-PCR analysis, OxyR (<italic>dgeo</italic>_1888) was highly up-regulated to 30-fold by oxidative stress through hydrogen peroxide treatment in both WT and Δ<italic>dgeo</italic>_2840 mutant strains. However, the oxidative stress response enzyme, catalase or superoxide dismutase, was not significantly induced by overexpressed OxyR. Thus, a putative LysR family regulator Dgeo_2840 controlled the expression of IS<italic>Dge6</italic> type transposase and the induction of OxyR under oxidative condition. There is LysR family DNA-binding protein dependent active transposition of specific type IS and the up-regulated OxyR has not positively controlled ROS scavenger enzymes in <italic>D. geothermalis</italic>.</p>