An RNA thermosensor controls expression of virulence genes in Listeria monocytogenes
An RNA thermosensor controls expression of virulence genes in Listeria monocytogenes
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DOI：
10.1016/s0092-8674(02)00905-4
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发表时间：
2002-09-06
期刊：
影响因子：
64.5
通讯作者：
Cossart, P
中科院分区：
文献类型：
--
作者：
Johansson, J;Mandin, P;Cossart, P
在单核细胞增生李斯特菌中，毒力基因在37 ℃时表达最多，在30 ℃时几乎沉默，并由PrfA控制，PrfA是一种转录激活因子，其表达受温度调节。在这里，我们表明，非翻译的mRNA（UTR）前prfA，形成一个二级结构，它掩盖了核糖体结合区。预测突变会破坏这种结构，导致毒性基因表达和在30 ℃下侵入哺乳动物细胞。化学探测、天然凝胶电泳、体外翻译以及“补偿性”和“增加稳定性”突变表明，UTR在高温下有活性的结构和低温下无活性的结构之间切换。引人注目的是，当对应于UTR的DNA与大肠杆菌中的gfp融合时，大肠杆菌，细菌在37 ℃时发出荧光，但在30 ℃时没有。这种转录后温度调节机制可能具有重要的应用。
In Listeria monocytogenes, virulence genes are maximally expressed at 37degreesC, almost silent at 30degreesC and controlled by PrfA, a transcriptional activator whose expression is thermoregulated. Here, we show that the untranslated mRNA (UTR) preceding prfA, forms a secondary structure, which masks the ribosome binding region. Mutations predicted to destabilize this structure led to virulence gene expression and invasion of mammalian cells at 30degreesC. Chemical probing, native gel electrophoresis, in vitro translation, and "compensatory" and "increased stability" mutations demonstrated that the UTR switches between a structure active at high temperatures, and another inactive at low temperatures. Strikingly, when the DNA corresponding to the UTR was fused to gfp in E. coli, bacteria became fluorescent at 37degreesC, but not at 30degreesC. This mechanism of posttranscriptional thermoregulation may have important applications.