Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain.
Institut de Bioenginyeria de Catalunya (IBEC), Baldiri i Reixac 10-12, 08028 Barcelona, Spain.
Microbiology (Reading). 2013 Mar;159(Pt 3):545-554. doi: 10.1099/mic.0.062448-0. Epub 2012 Dec 20.
Hha-like proteins are an evolutive trait of members of the family Enterobacteriaceae. These proteins mimic the oligomerization domain of the nucleoid-associated protein H-NS and interact with this latter protein to modulate gene expression. In this report, we provide evidence that, as has been shown for H-NS, Hha-like proteins play an essential role facilitating acquisition of horizontally transferred DNA in both Escherichia coli and Salmonella. Incorporation of conjugative plasmids such as pHly152 or R27 results in a fitness cost in E. coli or Salmonella strains that lack Hha-like proteins. E. coli spontaneous derivatives from double hha ydgT mutants that showed an increased growth rate and a restored fitness overexpressed the H-NS protein. In addition to reinforcing the role of H-NS/Hha-modulating xenogeneic DNA, the results obtained demonstrate that the Enterobacteriaceae display regulatory features not found in other bacteria that facilitate incorporation of horizontally transferred DNA.
Hha 样蛋白是肠杆菌科成员的进化特征。这些蛋白模拟核蛋白 H-NS 的寡聚化结构域，并与后者相互作用以调节基因表达。在本报告中，我们提供的证据表明，与 H-NS 一样，Hha 样蛋白在大肠杆菌和沙门氏菌中均发挥了重要作用，促进了水平转移 DNA 的获取。接合质粒如 pHly152 或 R27 的整合会导致缺乏 Hha 样蛋白的大肠杆菌或沙门氏菌菌株的适应性成本。大肠杆菌双 hha ydgT 突变体的自发衍生物表现出生长速度增加和适应性恢复，过表达 H-NS 蛋白。除了加强 H-NS/Hha 调节异种 DNA 的作用外，所得结果表明，肠杆菌科显示出其他细菌中未发现的调节特征，从而促进了水平转移 DNA 的整合。
