Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, WA, 98195, USA.
Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, WA, 98195, USA; Department of Microbiology, University of Washington School of Medicine, Seattle, WA, 98195, USA.
Curr Opin Microbiol. 2020 Jun;55:1-8. doi: 10.1016/j.mib.2020.01.002. Epub 2020 Feb 7.
Gene duplication facilitates the evolution of biological complexity, as one copy of a gene retains its original function while a duplicate copy can acquire mutations that would otherwise diminish fitness. Duplication has played a particularly important role in the evolution of regulatory networks by permitting novel regulatory interactions and responses to stimuli. The diverse MarR family of transcription factors (MFTFs) illustrate this concept, ranging from highly specific repressors of single operons to pleiotropic global regulators controlling hundreds of genes. MFTFs are often genetically and functionally linked to antimicrobial efflux systems. However, the SlyA MFTF lineage in the Enterobacteriaceae plays little or no role in regulating efflux but rather functions as transcriptional counter-silencers, which alleviate xenogeneic silencing of horizontally acquired genes and facilitate bacterial evolution by horizontal gene transfer. This review will explore recent advances in our understanding of MFTF traits that have contributed to their functional evolution.
基因复制促进了生物复杂性的进化，因为一个基因的一个拷贝保留了其原始功能，而一个重复的拷贝可以获得突变，否则这些突变会降低适应性。基因复制在调控网络的进化中发挥了特别重要的作用，因为它允许新的调控相互作用和对刺激的反应。多样化的 MarR 家族转录因子（MFTF）说明了这一概念，从高度特异性的单个操纵子抑制剂到控制数百个基因的多效性全局调节剂。MFTF 通常在遗传和功能上与抗生素外排系统相关联。然而，肠杆菌科中的 SlyA MFTF 谱系在调节外排方面几乎没有作用，而是作为转录反向沉默因子发挥作用，减轻水平获得基因的异种沉默，并通过水平基因转移促进细菌进化。这篇综述将探讨我们对 MFTF 特征的理解的最新进展，这些特征有助于它们的功能进化。
