Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Curr Opin Microbiol. 2017 Aug;38:22-29. doi: 10.1016/j.mib.2017.04.001. Epub 2017 Apr 27.
Naturally competent bacteria can pull free DNA from their surroundings. This incoming DNA can serve various purposes, ranging from acting as a source of nutrients or DNA stretches for repair to the acquisition of novel genetic information. The latter process defines the natural competence for transformation as a mode of horizontal gene transfer (HGT) and led to its discovery almost a century ago. However, although it is widely accepted that natural competence can contribute to the spread of genetic material among prokaryotes, the question remains whether this mode of HGT can foster the transfer of larger DNA regions or only transfers shorter fragments, given that extracellular DNA is often heavily fragmented. Here, I outline examples of competence-mediated movement of large genomic segments. Moreover, I discuss a recent proposition that transformation is used to cure bacteria of selfish mobile genetic elements. Such a transformation-mediated genome maintenance mechanism could indeed be an important and underappreciated function of natural competence.
天然感受态细菌可以从周围环境中提取游离 DNA。这些进入的 DNA 可以有多种用途，从作为营养物质或 DNA 片段修复的来源，到获得新的遗传信息。后一种过程将自然感受态定义为水平基因转移 (HGT) 的一种模式，并在近一个世纪前就发现了它。然而，尽管人们普遍认为自然感受态可以促进原核生物之间遗传物质的传播，但仍存在疑问，即这种 HGT 模式是否可以促进较大 DNA 区域的转移，或者仅转移较短的片段，因为细胞外 DNA 通常被严重碎片化。在这里，我概述了通过感受态介导的大型基因组片段移动的例子。此外，我还讨论了最近的一个观点，即转化被用来清除细菌中自私的移动遗传元件。这种转化介导的基因组维持机制确实可能是自然感受态的一个重要但未被充分认识的功能。
