Institute of Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA.
McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, USA.
Sci Rep. 2021 Jun 21;11(1):12949. doi: 10.1038/s41598-021-91335-8.
Networks of transcriptional and post-transcriptional regulators are critical for bacterial survival and adaptation to environmental stressors. While transcriptional regulators provide rapid activation and/or repression of a wide-network of genes, post-transcriptional regulators, such as small RNAs (sRNAs), are also important to fine-tune gene expression. However, the mechanisms of sRNAs remain poorly understood, especially in less-studied bacteria. Deinococcus radiodurans is a gram-positive bacterium resistant to extreme levels of ionizing radiation (IR). Although multiple unique regulatory systems (e.g., the Radiation and Desiccation Response (RDR)) have been identified in this organism, the role of post-transcriptional regulators has not been characterized within the IR response. In this study, we have characterized an sRNA, PprS (formerly Dsr2), as a post-transcriptional coordinator of IR recovery in D. radiodurans. PprS showed differential expression specifically under IR and knockdown of PprS resulted in reduced survival and growth under IR, suggesting its importance in regulating post-radiation recovery. We determined a number of potential RNA targets involved in several pathways including translation and DNA repair. Specifically, we confirmed that PprS binds within the coding region to stabilize the pprM (DR_0907) transcript, a RDR modulator. Overall, these results are the first to present an additional layer of sRNA-based control in DNA repair pathways associated with bacterial radioresistance.
转录和转录后调控网络对于细菌的生存和适应环境胁迫至关重要。虽然转录调控因子可以快速激活和/或抑制广泛的基因网络，但转录后调控因子，如小 RNA (sRNA)，对于精细调控基因表达也很重要。然而，sRNA 的作用机制仍知之甚少，特别是在研究较少的细菌中。耐辐射球菌是一种革兰氏阳性菌，能抵抗极高水平的电离辐射 (IR)。尽管在该生物体中已经鉴定出多个独特的调控系统（例如，辐射和干燥响应 (RDR)），但在 IR 反应中尚未对转录后调控因子的作用进行表征。在这项研究中，我们将 sRNA PprS（以前称为 Dsr2）鉴定为耐辐射球菌 IR 恢复的转录后协调因子。PprS 特异性地在 IR 下表达差异，并且 PprS 的敲低导致 IR 下的存活和生长减少，这表明其在调节辐射后恢复中的重要性。我们确定了涉及多个途径的许多潜在的 RNA 靶标，包括翻译和 DNA 修复。具体来说，我们证实 PprS 结合到编码区域内以稳定 RDR 调节剂 pprM (DR_0907) 的转录物。总的来说，这些结果首次提出了与细菌抗辐射性相关的 DNA 修复途径中基于 sRNA 的额外调控层。
