RsmA and the quorum-sensing signal, N-[3-oxohexanoyl]-L-homoserine lactone, control the levels of rsmB RNA in Erwinia carotovora subsp carotovora by affecting its stability
RsmA and the quorum-sensing signal, N-[3-oxohexanoyl]-L-homoserine lactone, control the levels of rsmB RNA in Erwinia carotovora subsp carotovora by affecting its stability
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DOI：
10.1128/jb.184.15.4089-4095.2002
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发表时间：
2002-08-01
影响因子：
3.2
通讯作者：
Chatterjee, AK
中科院分区：
文献类型：
--
作者：
Chatterjee, A;Cui, YY;Chatterjee, AK
RsmA（次级代谢调节剂）、RsmC 和 rsmB RNA（转录后调节系统的组成部分）控制胡萝卜软腐欧文氏菌亚种的细胞外蛋白质产生和致病性。胡萝卜科。 RsmA 是一种 RNA 结合蛋白，通过促进信息衰减充当负调节因子。另一方面，rsmB RNA 通过中和 RsmA 的作用充当正调节因子。 RsmC 通过正向调节 rsmA 和负向控制 rsmB 来调节 RsmA 和 rsmB RNA 的水平。 RsmA(+) 细菌中的 rsmB RNA 水平明显高于 RsmA(-) 突变体。我们发现 rsmB RNA 在 RsmA 存在的情况下比在 RsmA 不存在的情况下更稳定。 RsmA 不会刺激 rsmB-lacZ 转录融合体的表达；事实上，RsmA-细菌中的β-半乳糖苷酶水平略高于RsmA(+)细菌中的水平。我们还研究了在缺乏群体感应信号 N-[3-氧代己酰基]-L-高丝氨酸内酯 (OHL) 的情况下 rsmA 和 rsmB RNA 水平增加的基础。 OHL 的缺失会激活 rsmA 的转录，但不会激活 rsmB 的转录。相反，在 RsmA 存在下 rsmB RNA 的稳定性增加是 OHL 细菌中 rsmB RNA 水平升高的原因。突变研究表明，虽然RsmA、OHL和RsmC控制rsmB RNA的水平，但仅在RsmA(+)细菌中没有RsmC或OHL时才会出现高水平的rsmB RNA，这表明RsmA在调节rsmB RNA水平中发挥着关键作用。本文报告的研究结果证实，群体感应信号是在 E. carotovora subsp. 中传导的。胡萝卜素通过 rsmA-rsmB 转录后调节系统。
RsmA (for regulator of secondary metabolism), RsmC, and rsmB RNA, the components of a posttranscriptional regulatory system, control extracellular protein production and pathogenicity in Erwinia carotovora subsp. carotovora. RsmA, an RNA binding protein, acts as a negative regulator by promoting message decay. rsmB RNA, on the other hand, acts as a positive regulator by neutralizing the effect of RsmA. RsmC modulates the levels of RsmA and rsmB RNA by positively regulating rsmA and negatively controlling rsmB. The level of rsmB RNA is substantially higher in RsmA(+) bacteria than in RsmA(-) mutants. We show that rsmB RNA is more stable in the presence of RsmA than in its absence. RsmA does not stimulate the expression of an rsmB-lacZ transcriptional fusion; in fact, the P-galactosidase level is somewhat higher in RsmA- bacteria than in RsmA(+) bacteria. We also investigated the basis for increased levels of rsmA and rsmB RNAs in the absence of the quorum-sensing signal, N-[3-oxohexanoyl]-L-homoserine lactone (OHL). The absence of OHL activates transcription of rsmA but not of rsmB. Instead, increased stability of rsmB RNA in the presence of RsmA accounts for the elevated levels of the rsmB RNA in OHL- bacteria. Mutant studies disclosed that while RsmA, OHL, and RsmC control the levels of rsmB RNA, high levels of rsmB RNA occur in the absence of RsmC or OHL only in RsmA(+) bacteria, indicating a critical role for RsmA in modulating the levels of rsmB RNA. The findings reported here firmly establish that the quorum-sensing signal is channeled in E. carotovora subsp. carotovora via the rsmA-rsmB posttranscriptional regulatory system.