Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
BMC Microbiol. 2013 Jun 16;13:134. doi: 10.1186/1471-2180-13-134.
The RNA binding protein Hfq of Haemophilus influenzae is highly homologous to Hfq from other bacterial species. In many of these other bacteria, Hfq affects the expression of a broad range of genes and enhances the ability to respond to stressful environments. However, the role of Hfq in H. influenzae is unknown.
Deletion mutants of hfq were generated in the nontypeable H. influenzae strains R2866 and 86-028NP to assess the role of Hfq in these well characterized but genotypically and phenotypically divergent clinical isolates. A deletion mutation of hfq had no effect on growth of H. influenzae in nutrient rich media and had no effect on survival in several stressful conditions in vitro. However, the mutation resulted in a reduced ability to utilize heme from hemoglobin. The mutant and wild type strains were assessed for virulence and competitive fitness in models of invasive disease and otitis media. In the chinchilla model of otitis media, the hfq mutant of 86-028NP exhibited impaired competitive fitness when compared to its wild type progenitor but exhibited no apparent defect in virulence. In the infant rat model, deletion of hfq in R2866 resulted in reduced bacterial titers in blood and a shorter duration of infection when compared to the wild type strain in the competitive fitness study.
We conclude that Hfq is involved in the utilization of essential nutrients and facilitates infection by H. influenzae.
流感嗜血杆菌的 RNA 结合蛋白 Hfq 与其他细菌的 Hfq 高度同源。在许多其他细菌中，Hfq 影响广泛的基因表达，并增强了对胁迫环境的响应能力。然而，Hfq 在流感嗜血杆菌中的作用尚不清楚。
在非典型流感嗜血杆菌株 R2866 和 86-028NP 中生成了 hfq 缺失突变体，以评估 Hfq 在这些经过充分表征但在遗传和表型上存在差异的临床分离株中的作用。hfq 的缺失突变对流感嗜血杆菌在营养丰富的培养基中的生长没有影响，也没有对体外几种应激条件下的存活产生影响。然而，该突变导致利用血红蛋白中的血红素的能力降低。突变体和野生型菌株在侵袭性疾病和中耳炎模型中评估了毒力和竞争适应性。在中耳炎的豚鼠模型中，与野生型亲本相比，86-028NP 的 hfq 突变体显示出竞争适应性降低，但毒力没有明显缺陷。在婴儿大鼠模型中，与野生型菌株相比，R2866 中的 hfq 缺失导致血液中的细菌载量减少，感染持续时间缩短。
我们得出结论，Hfq 参与了必需营养素的利用，并促进了流感嗜血杆菌的感染。
