a Microbiology Unit, Interdisciplinary Biosciences , Belgian Nuclear Research Centre (SCK•CEN) , Mol , Belgium.
b Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre , Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering , KU Leuven , Leuven , Belgium.
Crit Rev Microbiol. 2017 Nov;43(6):709-730. doi: 10.1080/1040841X.2017.1303661. Epub 2017 Apr 13.
Transposable elements (TE), small mobile genetic elements unable to exist independently of the host genome, were initially believed to be exclusively deleterious genomic parasites. However, it is now clear that they play an important role as bacterial mutagenic agents, enabling the host to adapt to new environmental challenges and to colonize new niches. This review focuses on the impact of insertion sequences (IS), arguably the smallest TE, on bacterial genome plasticity and concomitant adaptability of phenotypic traits, including resistance to antibacterial agents, virulence, pathogenicity and catabolism. The direct consequence of IS transposition is the insertion of one DNA sequence into another. This event can result in gene inactivation as well as in modulation of neighbouring gene expression. The latter is usually mediated by de-repression or by the introduction of a complete or partial promoter located within the element. Furthermore, transcription and transposition of IS are affected by host factors and in some cases by environmental signals offering the host an adaptive strategy and promoting genetic variability to withstand the environmental challenges.
转座元件（TE）是一种小型的可移动遗传元件，不能独立于宿主基因组存在，最初被认为是纯粹的有害基因组寄生虫。然而，现在很清楚的是，它们作为细菌诱变剂起着重要作用，使宿主能够适应新的环境挑战并占领新的生态位。这篇综述重点介绍了插入序列（IS）的影响，IS 可以说是最小的转座元件，它对细菌基因组的可塑性和表型特征的伴随适应性有影响，包括对抗生素的耐药性、毒力、致病性和分解代谢。IS 转座的直接后果是将一个 DNA 序列插入另一个 DNA 序列。这一事件既可能导致基因失活，也可能导致邻近基因表达的调节。后一种情况通常是通过去阻遏或通过引入位于元件内的完整或部分启动子来介导的。此外，IS 的转录和转座受到宿主因子的影响，在某些情况下还受到环境信号的影响，为宿主提供了一种适应策略，并促进了遗传变异，以抵御环境挑战。
