Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA.
Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA.
Trends Genet. 2021 Jan;37(1):59-72. doi: 10.1016/j.tig.2020.09.004. Epub 2020 Sep 29.
Many bacterial species generate phenotypically heterogeneous subpopulations as a strategy for ensuring the survival of the population as a whole - an environmental stress that eradicates one subpopulation may leave other phenotypic groups unharmed, allowing the lineage to continue. Phase variation, a process that functions as an ON/OFF switch for gene expression, is one way that bacteria achieve phenotypic heterogeneity. Phase variation occurs stochastically and reversibly, and in the presence of a selective pressure the advantageous phenotype(s) predominates in the population. Phase variation can occur through multiple genetic and epigenetic mechanisms. This review focuses on conservative site-specific recombination that generates reversible DNA inversions as a genetic mechanism mediating phase variation. Recent studies have sparked a renewed interest in phase variation mediated through DNA inversion, revealing a high level of complexity beyond simple ON/OFF switching, including unusual modes of gene regulation, and highlighting an underappreciation of the use of these mechanisms by bacteria.
许多细菌物种会产生表型异质的亚群，这是确保整个种群生存的一种策略——一种环境压力可能会消灭一个亚群，但其他表型群体可能不会受到伤害，从而使谱系得以延续。相位变异是一种基因表达的开/关开关，是细菌实现表型异质性的一种方式。相位变异是随机和可逆的，在选择性压力下，有利的表型在种群中占优势。相位变异可以通过多种遗传和表观遗传机制发生。这篇综述重点介绍了保守的位点特异性重组，它产生可逆的 DNA 倒位，作为介导相位变异的遗传机制。最近的研究激发了人们对通过 DNA 倒位介导的相位变异的重新兴趣，揭示了超出简单开/关开关的高水平复杂性，包括不寻常的基因调控模式，并强调了人们对细菌使用这些机制的认识不足。
