Le Casin, Pimentel Camila, Tuttobene Marisel R, Subils Tomás, Escalante Jenny, Nishimura Brent, Arriaga Susana, Rodgers Deja, Bonomo Robert A, Sieira Rodrigo, Tolmasky Marcelo E, Ramírez María Soledad
Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA.
Área Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario S2002LRK, Argentina.
Pathogens. 2021 Aug 26;10(9):1083. doi: 10.3390/pathogens10091083.
Most strains are naturally competent. Although some information is available about factors that enhance or reduce the frequency of the transformation of this bacterium, the regulatory elements and mechanisms are barely understood. In this article, we describe studies on the role of the histone-like nucleoid structuring protein, H-NS, in the regulation of the expression of genes related to natural competency and the ability to uptake foreign DNA. The expression levels of the natural transformation-related genes , , , , , , and significantly increased in a Δ derivative of A118. The complementation of the mutant with a recombinant plasmid harboring restored the expression levels of six of these genes ( remained expressed at high levels) to those of the wild-type strain. The transformation frequency of the A118 Δ strain was significantly higher than that of the wild-type. Similar, albeit not identical, there were consequences when was deleted from the hypervirulent AB5075 strain. In the AB5075 complemented strain, the reduction in gene expression in a few cases was not so pronounced that it reached wild-type levels, and the expression of was enhanced further. In conclusion, the expression of all seven transformation-related genes was enhanced after deleting in A118 and AB5075, and these modifications were accompanied by an increase in the cells' transformability. The results highlight a role of H-NS in natural competence.
大多数菌株具有天然感受态。尽管已有一些关于增强或降低该细菌转化频率的因素的信息，但调控元件和机制仍几乎不为人所知。在本文中，我们描述了关于类组蛋白核仁结构蛋白H-NS在调控与天然感受态及摄取外源DNA能力相关基因表达中的作用的研究。在A118的Δ衍生物中，与天然转化相关的基因、、、、、、和的表达水平显著增加。用携带的重组质粒对突变体进行互补，使其中六个基因的表达水平（仍高水平表达）恢复到野生型菌株的水平。A118 Δ菌株的转化频率显著高于野生型。类似地，尽管不完全相同，当从高毒力的AB5075菌株中缺失时也有相应结果。在AB5075互补菌株中，少数情况下基因表达的降低并不显著，以至于未达到野生型水平，并且的表达进一步增强。总之，在A118和AB5075中缺失后，所有七个与转化相关的基因的表达均增强，并且这些修饰伴随着细胞转化能力的增加。结果突出了H-NS在天然感受态中的作用。
