Burkholderia mallei and Burkholderia pseudomallei cluster 1 type VI secretion system gene expression is negatively regulated by iron and zinc.
Burkholderia mallei and Burkholderia pseudomallei cluster 1 type VI secretion system gene expression is negatively regulated by iron and zinc.
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DOI：
10.1371/journal.pone.0076767
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Brett PJ
中科院分区：
文献类型：
--
作者：
Burtnick MN;Brett PJ
马氏伯克霍尔德氏菌是一种兼性细胞内病原体，可引起人类和动物的腺体炎。先前的研究表明，该生物表达的簇1型VI分泌系统（T6SS-1）对仓鼠毒力至关重要，并受到VirAG双组分系统的正调控。最近，我们发现T6SS-1基因表达在病原体内化进入吞噬细胞后上调，并且该系统促进了感染组织培养单层中多核巨细胞的形成。在本研究中，我们进一步研究了这一重要毒力因子的复杂调控。为了评估T6SS-1的表达，在不同的培养基条件下培养mallei B.菌株，并通过Western免疫印迹法分析Hcp1的产生。同时利用实时荧光定量PCR技术检测了多个virag调控基因（bimA、tssA、hcp1和tssM）的转录水平。与之前的观察结果一致，T6SS-1在富培养基中不表达。奇怪的是，在最小培养基（M9G）或最小培养基加酪胺酸（M9CG）中生长的生物体促进了T6SS-1基因的强烈表达，而在最小培养基加色氨酸（M9TG）中生长的生物体则没有。对这一现象的研究证实了VirAG在这一过程中的调节作用。此外，在M9CG中添加铁和锌显著下调T6SS-1基因的表达。在VirAG控制下的其他基因似乎没有受到这些二价金属的严格调节。假麦氏芽孢杆菌也有类似的结果，而泰国芽孢杆菌则没有。总的来说，我们的研究结果表明，除了受VirAG的正调控外，B. mallei和B. pseudomallei T6SS-1基因的表达还受到铁和锌的负调控。
Burkholderia mallei is a facultative intracellular pathogen that causes glanders in humans and animals. Previous studies have demonstrated that the cluster 1 type VI secretion system (T6SS-1) expressed by this organism is essential for virulence in hamsters and is positively regulated by the VirAG two-component system. Recently, we have shown that T6SS-1 gene expression is up-regulated following internalization of this pathogen into phagocytic cells and that this system promotes multinucleated giant cell formation in infected tissue culture monolayers. In the present study, we further investigated the complex regulation of this important virulence factor. To assess T6SS-1 expression, B. mallei strains were cultured in various media conditions and Hcp1 production was analyzed by Western immunoblotting. Transcript levels of several VirAG-regulated genes (bimA, tssA, hcp1 and tssM) were also determined using quantitative real time PCR. Consistent with previous observations, T6SS-1 was not expressed during growth of B. mallei in rich media. Curiously, growth of the organism in minimal media (M9G) or minimal media plus casamino acids (M9CG) facilitated robust expression of T6SS-1 genes whereas growth in minimal media plus tryptone (M9TG) did not. Investigation of this phenomenon confirmed a regulatory role for VirAG in this process. Additionally, T6SS-1 gene expression was significantly down-regulated by the addition of iron and zinc to M9CG. Other genes under the control of VirAG did not appear to be as tightly regulated by these divalent metals. Similar results were observed for B. pseudomallei, but not for B. thailandensis. Collectively, our findings indicate that in addition to being positively regulated by VirAG, B. mallei and B. pseudomallei T6SS-1 gene expression is negatively regulated by iron and zinc.
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影响因子：
3.2
作者：
DeShazer, D;Brett, PJ;Woods, DE
通讯作者：
Woods, DE
用于选择特工Burkholderia pseudomallei和Burkholderia Mallei的符合遗传操作的等位基因交换系统。
影响因子：
3.5
作者：
Hamad, Mohamad A.;Zajdowicz, Sheryl L.;Holmes, Randall K.;Voskuil, Martin I.
通讯作者：
Voskuil, Martin I.
影响因子：
4.5
作者：
Brunet YR;Bernard CS;Gavioli M;Lloubès R;Cascales E
通讯作者：
Cascales E
DOI：
10.1099/00207713-48-1-317
发表时间：
1998-01-01
期刊：
INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY
影响因子：
--
作者：
Brett, PJ;DeShazer, D;Woods, DE
通讯作者：
Woods, DE
影响因子：
3.1
作者：
Aubert, Daniel F.;Flannagan, Ronald S.;Valvano, Miguel A.
通讯作者：
Valvano, Miguel A.