Identification of CsrC and characterization of its role in epithelial cell invasion in Salmonella enterica serovar Typhimurium
Identification of CsrC and characterization of its role in epithelial cell invasion in Salmonella enterica serovar Typhimurium
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DOI：
10.1128/iai.74.1.331-339.2006
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发表时间：
2006-01-01
影响因子：
3.1
通讯作者：
Altier, C
中科院分区：
文献类型：
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作者：
Fortune, DR;Suyemoto, M;Altier, C
沙门氏菌csr调控系统调控沙门氏菌侵染上皮细胞所需的致病性岛1 （SPI1）基因的表达。该系统由转录后调控RNA CsrA和一种非翻译的调控RNA CsrB组成，该RNA反对CsrA的作用。在这里，我们确定并表征了第二种调控RNA CsrC的作用，其同源物先前在大肠杆菌中被发现。我们发现，与csrB突变体一样，证监会突变体在入侵和SPI1基因表达方面只有轻微缺陷，但双重csrB证监会突变体在这些特性上明显缺乏，这表明这两种调控rna在控制入侵中发挥了冗余作用。我们进一步表明，像CsrB一样，CsrC也受到BarA/SirA双组分调控因子的控制，但CsrB CsrC突变体表现出与BarA或SirA突变体相当的入侵损失，这表明BarA/SirA通过控制CsrB和证监会对入侵功能产生很大影响。除了由BarA/SirA控制外，每种调节RNA还由csr系统的其他组分控制。研究发现，中国证监会的缺失使中国证监会的水平提高了7倍，而中国证监会的缺失使中国证监会的水平提高了近两倍。同样，csrA的过表达使CsrC增加了近11倍，CsrB增加了3倍，并且显著提高了这两种rna的稳定性。
The csr regulatory system of Salmonella regulates the expression of the genes of Salmonella pathogenicity island 1 (SPI1) required for the invasion of epithelial cells. This system consists of the posttranscriptional regulator CsrA and an untranslated regulatory RNA, CsrB, that opposes the action of CsrA. Here we identify and characterize the role of a second regulatory RNA, CsrC, whose ortholog was discovered previously in Escherichia coli. We show that a mutant of csrC has only mild defects in invasion and the expression of SPI1 genes, as does a mutant of csrB, but that a double csrB csrC mutant is markedly deficient in these properties, suggesting that the two regulatory RNAs play redundant roles in the control of invasion. We further show that CsrC, like CsrB, is controlled by the BarA/SirA two-component regulator but that a csrB csrC mutant exhibits a loss of invasion equivalent to that of a barA or sirA mutant, indicating that much of the effect of BarA/SirA on invasion functions through its control of CsrB and CsrC. In addition to their control by BarA/SirA, each regulatory RNA is also controlled by other components of the csr system. The loss of csrB was found to increase the level of CsrC by sevenfold, while the loss of csrC increased CsrB by nearly twofold. Similarly, the overexpression of csrA increased CsrC by nearly 11-fold and CsrB by 3-fold and also significantly increased the stability of both RNAs.