Expression of FLJB:Z66 on a Linear Plasmid of Salmonella Enterica Serovar Typhi is Dependent on FLIA and FLHDC and Regulated By OMPR.
Expression of FLJB:Z66 on a Linear Plasmid of Salmonella Enterica Serovar Typhi is Dependent on FLIA and FLHDC and Regulated By OMPR.
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DOI：
10.1590/s1517-83822010000300025
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发表时间：
2010-07
期刊：
影响因子：
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通讯作者：
Huang X
中科院分区：
文献类型：
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作者：
Xu S;Zou X;Sheng X;Zhang H;Mao L;Du H;Xu H;Huang X
大肠沙门氏菌血清型伤寒z66阳性菌株的鞭毛蛋白基因fliC:d/j和fljB:z66分别位于染色体和线性质粒上。为了研究fljB:z66表达调控的机制，本研究构建了fljB:z66调控因子FliA、FlhDC和OmpR的基因缺失突变体。采用qRT-PCR分析了高、低渗透压条件下野生型菌株和突变体中fllic和fljB:z66的表达水平。结果表明，在高渗透和低渗透条件下，fljB:z66和fliC在fla和flhDC突变体中的表达量均显著降低。在ompR突变体中，fljB:z66、fliC、fla和flhD的表达水平在低渗透条件下增加。SDS-PAGE和western blotting分析显示，在高渗透压和低渗透压条件下，FljB:z66在fla和flhDC突变体中几乎不存在。在野生型菌株中，fljB:z66在高渗透压条件下的表达量高于低渗透压条件。然而，这种表达差异在ompR突变体中消失了。FljB:z66的翻译表达实验表明，在低渗透压和高渗透压条件下，FljB:z66在ompR突变体中的表达均降低。这些结果表明，fljB:z66在伤寒沙门氏菌血清型中表达依赖于FliA和FlihDC，而OmpR可以调节不同渗透压下fljB:z66的表达和分泌。
Salmonella enterica serovar Typhi z66-positive strains have two different flagellin genes, fliC:d/j and fljB:z66, located on the chromosome and on a linear plasmid, respectively. To investigate the mechanism underlying the expressional regulation of fljB:z66, gene deletion mutants of the regulators FliA, FlhDC, and OmpR were constructed in this study. The expression levels of fliC and fljB:z66 were analyzed by qRT–PCR in the wild-type strain and mutants at high and low osmolarity. The results show that the expression levels of both fljB:z66 and fliC were greatly reduced in fliA and flhDC mutants under both high and low osmotic conditions. In the ompR mutant, the expression levels of fljB:z66, fliC, fliA, and flhD were increased at low osmotic conditions. SDS-PAGE and western blotting analysis of the secreted proteins revealed that the FljB:z66 was almost absent in the fliA and flhDC mutants at both high and low osmolarity. In the wild-type strain, the fljB:z66 was more highly expressed under high-osmolarity conditions than under low-osmolarity conditions. However, this difference in expression disappeared in the ompR mutant. Translational expression assay of FljB:z66 showed that the FljB:z66 expression was decreased in ompR mutant at both low and high osmolarity. These results suggest that the expression of fljB:z66 in S. enterica serovar Typhi is dependent on FliA and FlihDC, and OmpR can regulate the expression and secretion of FljB:z66 in different osmolarity.