Dorman Charles J, Kane Kelly A
Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland.
FEMS Microbiol Rev. 2009 May;33(3):587-92. doi: 10.1111/j.1574-6976.2008.00155.x. Epub 2008 Dec 22.
Horizontal DNA transfer plays a major role in the evolution of bacteria. It allows them to acquire new traits rapidly and these may confer fitness advantages as the bacteria compete with others in the environment. Historically, the mechanisms of horizontal DNA transfer, chiefly conjugation, transformation and transduction, have received a great deal of attention. Less attention has been focused on the regulatory problems that may accompany the acquisition of new genes by lateral routes. How are these genes integrated into the existing regulatory circuits of the cell? Does a process of 'plug-and-play' operate, or are the new genes silenced pending the evolution of regulatory mechanisms that make their expression not only safe but also beneficial to both the gene and its new host? Recent research shows that bacterial nucleoid-associated proteins such as H-NS, HU and Fis are important contributors to the processes of regulatory integration that accompany horizontal gene transfer. A key emerging theme is the antagonism that exists between the DNA-protein-DNA bridging activity of the H-NS repressor and the DNA-bending and DNA-wrapping activities of regulatory proteins that oppose H-NS.
水平DNA转移在细菌进化中起着重要作用。它使细菌能够迅速获得新特性，而这些特性在细菌与环境中的其他细菌竞争时可能赋予其适应性优势。从历史上看，水平DNA转移的机制，主要是接合、转化和转导，受到了大量关注。较少的注意力集中在通过侧向途径获得新基因可能伴随的调控问题上。这些基因是如何整合到细胞现有的调控回路中的？“即插即用”过程是否起作用，或者新基因是否会保持沉默，直到调控机制进化到使其表达不仅安全而且对基因及其新宿主都有益？最近的研究表明，诸如H-NS、HU和Fis等细菌类核相关蛋白是伴随水平基因转移的调控整合过程的重要贡献者。一个关键的新出现的主题是H-NS阻遏物的DNA-蛋白质-DNA桥连活性与对抗H-NS的调控蛋白的DNA弯曲和DNA包裹活性之间存在的拮抗作用。
