Active Transposition of Insertion Sequences in Prokaryotes: Insights from the Response of Deinococcus geothermalis to Oxidative Stress

Abstract

Bacterial genomes contain numerous insertion sequences (ISs) as transposable elements involved in actions such as the sequestration, transmission, mutation and activation of genes that can influence the responsive capacity of the organism to environmental challenges. To date, at least 30 IS families have been identified. In this review, we describe how certain ISs are transposed to carotenoid biosynthesis genes, such as phytoene synthase and phytoene desaturase, when radiation-resistant Deinococcus geothermalis with a redox imbalance and a targeted gene disruption mutation is exposed to oxidative stressors, such as gamma-irradiation, dielectric bilayer discharge plasma and hydrogen peroxide. We also explain the genetic features of IS elements, spontaneous mutation and various stress responses, including nutrient limitation, and physicochemical and oxidative stress, associated with the active transposition of bacterial ISs. Based on the current knowledge, we posit that the redox signalling mechanism inducing IS transposition involves redox sensing and redox switching for the activation of transposase expression and its activity.

Hydrogen peroxide treatment induces the transposition of an insertion sequence in Deinococcus radiopugnans DY59

“…Several IS elements were actively transposed into other genome loci through the copy-and-paste mechanism of ISDge5, ISDge6, and ISDge7 members under hydrogen peroxide (H 2 O 2 )-induced oxidative stress. Furthermore, we reported the occurrence of a colorless phenotype through the loss of carotenoid biosynthesis via IS transposition, which was supported by several lines of evidence (Tian and Hua, 2010;Lee et al, 2019Lee et al, , 2020Ye et al, 2021;Shin et al, 2022). Research on the insertion sequence of bacteria can be conducted from a molecular evolution perspective, including cutting-edge mutagenesis using transposable elements to examine the plasticity of bacterial genomes induced by long-term culture or oxidative stress.…”

The Transposition of Insertion Sequences in Sigma-Factor- and LysR-Deficient Mutants of Deinococcus geothermalis

“…Based this study’s data, IS elements inserted in transposition loci are influenced by several conditions, including extracellular stress and the type of disrupted gene [ 43 ]. Therefore, the question is whether the specific IS elements involved in transposition depend on intrinsic factors, such as a sigma factor and LysR, and extracellular stress conditions, such as oxidative H 2 O 2 and gamma irradiation stress.…”