Lehrstuhl für Biologie der Mikroorganismen, Ruhr-Universität Bochum, Bochum, Germany.
J Bacteriol. 2012 Oct;194(19):5209-17. doi: 10.1128/JB.00510-12. Epub 2012 Jul 20.
The Hfq protein mediates gene regulation by small RNAs (sRNAs) in about 50% of all bacteria. Depending on the species, phenotypic defects of an hfq mutant range from mild to severe. Here, we document that the purified Hfq protein of the plant pathogen and natural genetic engineer Agrobacterium tumefaciens binds to the previously described sRNA AbcR1 and its target mRNA atu2422, which codes for the substrate binding protein of an ABC transporter taking up proline and γ-aminobutyric acid (GABA). Several other ABC transporter components were overproduced in an hfq mutant compared to their levels in the parental strain, suggesting that Hfq plays a major role in controlling the uptake systems and metabolic versatility of A. tumefaciens. The hfq mutant showed delayed growth, altered cell morphology, and reduced motility. Although the DNA-transferring type IV secretion system was produced, tumor formation by the mutant strain was attenuated, demonstrating an important contribution of Hfq to plant transformation by A. tumefaciens.
Hfq 蛋白在大约 50%的细菌中通过小 RNA（sRNA）介导基因调控。根据物种的不同，hfq 突变体的表型缺陷从轻微到严重不等。在这里，我们证明了植物病原体和天然遗传工程师农杆菌的纯化 Hfq 蛋白与先前描述的 sRNA AbcR1 及其靶 mRNA atu2422 结合，atu2422 编码 ABC 转运体的底物结合蛋白，该转运体摄取脯氨酸和γ-氨基丁酸（GABA）。与亲本菌株相比，hfq 突变体中几种其他 ABC 转运体成分的产量过高，这表明 Hfq 在控制农杆菌的摄取系统和代谢多功能性方面发挥着重要作用。hfq 突变体的生长速度较慢，细胞形态发生改变，运动能力下降。尽管产生了 DNA 转移的 IV 型分泌系统，但突变菌株的肿瘤形成能力减弱，这表明 Hfq 对农杆菌的植物转化有重要贡献。
