Brucella Stationary Phase Gene Expression and Virulence

Hfq是一种rna结合蛋白，在基因转录后调控中发挥多种作用。 在细菌中表达。在有问题的基因是转录调节基因的情况下，存在或 Hfq的缺失也会影响受其控制的基因亚集的表达模式。 调整器。我们实验室以前的研究表明，Hfq是狂犬病野生型毒力所必需的 小鼠模型中布氏杆菌流产2308株。到目前为止，我们已经确定了&gt；40个需要Hfq的基因 野生型在该菌株中的表达，以及其中的7个(SODC、ahpCD、VIRB、bvrRS、omp25、cydAB和znuA) 是小鼠致死所必需的！RT-PCR分析表明，SODC、ahpCD、virB和cydAB 6.流产2308中Hfq依赖和非Hfq依赖的转录模式，而bvrRs 在所有已检测的实验条件下，转录似乎都依赖于Hfq。 这些实验结果表明，转录激活剂或另一种CTF作为一种 Hfq与B.SODC、bvrRs、VIRB和cydAB野生型表达之间的中间调控链接 流产2308号。然而，我们对流产杆菌替代因子a无效突变体的表型分析表明 另一种因素没有发挥这种作用.因此，为了更好地了解 在B.bortus 2308中，Hfq与SODC、ahpCD、VIRB、bvrRs和cydAB之间的调控联系，具体 本申请中概述的研究的目的是：a)检验转录激活物是 负责SODC、ahpCD、bvrRs、VIRB和cydAB在该菌株中依赖于Hfq的表达；b) 确定这种依赖于Hfq的转录调节因子(HtcR)；以及c)确定HtcR- 苏云金芽胞杆菌的毒力依赖于SODC、ahpCD、bvrRs、VIRB和cydAB启动子区域。 小鼠流产2308例。从拟议研究中获得的信息将提供对 布鲁氏菌在哺乳动物体内驻留期间调节其基因表达的机制 宿主，这样的信息应该有助于设计新的候选疫苗并改进 化疗方法。这些研究还可能确定一种调节静止状态的新机制 阶段基因在原核生物中的表达。布鲁氏菌属。不拥有备选A的同源 在许多革兰氏阴性菌中执行这一功能的rpos因子，但hfq似乎是 SocfC、ahpCD、VIRB和cydAB在流产杆菌2308中的高效稳定表达。

Hfq is an RNA binding protein that plays multiple roles in the post-transcriptional regulation of gene expression in bacteria. In cases where the gene in question is a transcriptional regulator, the presence or absence of Hfq can also influence the expression patterns of the subsets of genes controlled by this regulator. Previous studies in our laboratory have shown that Hfq is required for the wild-type virulence of Brucella abortus 2308 in the mouse model. To date, we have identified > 40 genes that require Hfq for their wild-type expression in this strain, and seven of these (sodC, ahpCD, virB, bvrRS, omp25, cydAB and znuA) are necessary for virulence in mice! RT-PCR analysis indicates that sodC, ahpCD, virB.and cydAB display both Hfq-dependent and Hfq-independent patterns of transcription in 6. abortus 2308, while bvrRS transcription appears to be Hfq-dependent under all experimental conditions that have been examined. These experimental findings suggest that a transcriptional activator or alternativeCTfactor serves as an intermediate regulatory link between Hfq and wild-type expression of sodC, bvrRS, virB and cydAB in B. abortus 2308. Our phenotypic analyses of B. abortus alternative factor a null mutants, however, suggest that an alternative a factor is not playing this role. Consequently, in order to gain a better understanding of the regulatory link between Hfq and sodC, ahpCD, virB, bvrRS, and cydAB in B. abortus 2308, the specific aims of the studies outlined in this application are a) to test the hypothesis that a transcriptional activator is responsible for Hfq-dependent expression of sodC, ahpCD, bvrRS, virB and cydAB in this strain; b) to identify this Hfq-dependent transcriptional regulator (HtcR); and c) to determine the extent to which the HtcR- dependent promoter regions of sodC, ahpCD, bvrRS, virB and cydAB are required for the virulence of B. abortus 2308 in mice. Information derived from the proposed studies will provide insight into the mechanisms by which the brucellae regulate their gene expression during residence in their mammalian hosts, and such information should be useful for the design of novel vaccine candidates and improved chemotherapeutic approaches. These studies may also identify a novel mechanism for regulating stationary phase gene expression in prokaryotes. The Brucella spp. do not possess a homolog of the alternative a factor RpoS which performs this function in many Gram-negative bacteria, but Hfq appears to be required for the efficient stationary phase expression of socfC, ahpCD, virB and cydAB in B. abortus 2308.