Cell-wall synthesis and ribosome maturation are co-regulated by an RNA switch in Mycobacterium tuberculosis
Cell-wall synthesis and ribosome maturation are co-regulated by an RNA switch in Mycobacterium tuberculosis
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DOI：
10.1101/232314
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发表时间：
2017-12
影响因子：
14.9
通讯作者：
S. Schwenk;Alexandra Moores;Irene Nobeli;Timothy D McHugh;Kristine B. Arnvig
中科院分区：
文献类型：
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作者：
S. Schwenk;Alexandra Moores;Irene Nobeli;Timothy D McHugh;Kristine B. Arnvig
结核分枝杆菌作为病原体的成功依赖于在活跃生长和非复制持久性之间转换的能力，这与潜伏性结核感染有关。复苏促进因子（Rpfs）是M.结核病休眠和出现的非复制持续状态。但这些酶是双刃剑，因为它们降解细胞壁的能力对细菌本身是潜在的致命的。因此，Rpf表达受到严格调控。我们在rpfB的5'非翻译区（UTR）中鉴定了一个新的调控元件。我们证明，这个元素是一个转录调控的RNA开关/核糖开关候选人，这是仅限于致病性分枝杆菌，这表明在毒力的作用。此外，我们已经使用翻译起始位点作图来重新注释RpfB起始密码子，并鉴定和验证了可能被RpfB反义RNA靶向的核糖体结合位点。最后，我们表明，rpfB与下游基因，ksgA和ispE共转录。ksgA编码一种参与核糖体成熟的普遍保守的甲基转移酶，ispE编码一种参与细胞壁合成的必需ATP依赖性激酶。这种排列意味着通过RNA开关共同调节复苏、细胞壁合成和核糖体成熟。我们认为，这种开关的失调，与细胞壁合成和核糖体功能，提出了一个新的目标，抗结核药物的开发。重要性这项工作描述了一种新的调控RNA元件/衰减子的鉴定和表征，该元件控制结核分枝杆菌（人类结核病（TB）的病原体）中的细胞壁合成和核糖体功能。通过在两种不同构象之间切换，该RNA开关可以使能或抑制三顺反子mRNA的转录，所述三顺反子mRNA编码对潜伏性TB的活化至关重要的细胞壁重塑酶、对核糖体功能重要的RNA甲基转移酶和对细胞壁合成的早期步骤至关重要的蛋白激酶。这种RNA开关仅存在于致病性分枝杆菌的一个子集中，通过调节与经典抗菌靶标相关的三个基因的表达，我们相信它为未来的抗结核药物提供了一个新的重要靶标。
The success of Mycobacterium tuberculosis as a pathogen relies on the ability to switch between active growth and non-replicating persistence, associated with latent TB infection. Resuscitation promoting factors (Rpfs) are essential for the transition of M. tuberculosis to dormancy and for emergence from the non-replicating persistent state. But these enzymes are double-edged swords, as their ability to degrade the cell wall, is potentially lethal to the bacterium itself. Hence, Rpf expression is tightly regulated. We have identified a novel regulatory element in the 5’ untranslated region (UTR) of rpfB. We demonstrate that this element is a transcriptionally regulated RNA switch/riboswitch candidate, which is restricted to pathogenic mycobacteria, suggesting a role in virulence. Moreover, we have used translation start site mapping to re-annotate the RpfB start codon and identified and validated a ribosome binding site that is likely to be targeted by an RpfB antisense RNA. Finally, we show that rpfB is co-transcribed with downstream genes, ksgA and ispE. ksgA encodes a universally conserved methyl transferase involved in ribosome maturation and ispE encodes an essential ATP-dependent kinase involved in cell wall synthesis. This arrangement implies co-regulation of resuscitation, cell wall synthesis and ribosome maturation via the RNA switch. We propose that deregulation of this switch, associated with cell wall synthesis and ribosome function, presents a new target for anti-tuberculosis drug development. Importance This work describes the identification and characterisation of a novel regulatory RNA element/attenuator that controls cell wall synthesis and ribosome function in Mycobacterium tuberculosis, the causative agent of human tuberculosis (TB). By switching between two different conformations, this RNA switch can either enable or inhibit transcription of a tri-cistronic mRNA that encodes a cell-wall remodelling enzyme crucial for activation of latent TB, an RNA methytransferase that is important for ribosome function and a protein kinase essential for early steps in cell wall synthesis. This RNA switch is only present in a subset of pathogenic mycobacteria, and by regulating the expression of three genes associated with classical antimicrobial targets we believe that it offers a novel important target for future anti-tuberculosis drugs.