Department of Microbiology, Bose Institute, P-1/12 C.I.T Road. Scheme VIIM, Kolkata-700054, West Bengal, India.
Present address: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
Microbiology (Reading). 2022 Mar;168(3). doi: 10.1099/mic.0.001158.
Mycobacteriophage D29 infects species belonging to the genus Mycobacterium including the deadly pathogen Mycobacterium tuberculosis. D29 is a lytic phage, although, related to the lysogenic mycobacteriophage L5. This phage is unable to lysogenize in mycobacteria as it lacks the gene encoding the phage repressor. Infection by many mycobacteriophages cause various changes in the host that ultimately leads to inactivation of the latter. One of the host targets often modified in the process is RNA polymerase. During our investigations with phage D29 infected (Msm) we observed that the promoters from both phage, and to a lesser extent those of the host were found to be more active in cells that were exposed to D29, as compared to the unexposed. Further experiments indicate that the RNA polymerase purified from phage infected cells possessed higher affinity for promoters particularly those that were phage derived. Comparison of the purified RNA polymerase preparations from infected and uninfected cells showed that several ancillary transcription factors, Sigma factor F, Sigma factor H, CarD and RbpA are prominently associated with the RNA polymerase from infected cells. Based on our observations we conclude that the higher activity of RNA polymerase observed in D29 infected cells is due to its increased association with ancillary transcription factors.
噬菌 D29 可感染分枝杆菌属的物种，包括致命病原体结核分枝杆菌。D29 是一种裂解噬菌体，尽管它与溶原性分枝杆菌噬菌体 L5 有关。由于该噬菌体缺乏编码噬菌体阻遏物的基因，因此无法在分枝杆菌中溶原化。许多噬菌体会导致宿主发生各种变化，最终导致后者失活。在感染过程中经常被修饰的宿主靶标之一是 RNA 聚合酶。在我们用噬菌体 D29 感染的（Msm）研究过程中，我们观察到与未暴露于 D29 的细胞相比，暴露于 D29 的细胞中的噬菌体和宿主的启动子的活性更高。进一步的实验表明，从噬菌体感染细胞中纯化的 RNA 聚合酶对启动子具有更高的亲和力，特别是那些源自噬菌体的启动子。比较来自感染和未感染细胞的纯化 RNA 聚合酶制剂表明，几个辅助转录因子，Sigma 因子 F、Sigma 因子 H、CarD 和 RbpA 与来自感染细胞的 RNA 聚合酶显著相关。基于我们的观察结果，我们得出结论，D29 感染细胞中观察到的 RNA 聚合酶的更高活性是由于其与辅助转录因子的增加关联。
