Department of Microbiology, Bose Institute, P-1/12 C.I.T. Scheme VIIM, Kolkata-700054, India.
FEMS Microbiol Lett. 2020 Nov 23;367(21). doi: 10.1093/femsle/fnaa176.
Mycobacteriophages are phages that infect and kill Mycobacteria, several of which, Mycobacterium tuberculosis (Mtb), for example, cause the disease tuberculosis. Although genomes of many such phages have been sequenced, we have very little insight into how they express their genes in a controlled manner. To address this issue, we have raised a temperature-sensitive (ts) mutant of phage D29 that can grow at 37°C but not at 42°C and used it to perform differential gene expression and proteome analysis studies. Our analysis results indicate that expression of genes located in the right arm, considered to be early expressed, was lowered as the temperature was shifted from 37°C to 42°C. In contrast, expression of those on the left, the late genes were only marginally affected. Thus, we conclude that transcription of genes from the two arms takes place independently of each other and that a specific factor must be controlling the expression of the right arm genes. We also observe that within the right arm itself; there exists a mechanism to ensure high-level synthesis of Gp48, a thymidylate synthase X. Enhanced presence of this protein in infected cells results in delayed lysis and higher phage yields.
分枝杆菌噬菌体是感染并杀死分枝杆菌的噬菌体，其中几种，例如结核分枝杆菌（Mtb），会导致结核病。尽管已经对许多此类噬菌体的基因组进行了测序，但我们对它们如何以受控的方式表达基因知之甚少。为了解决这个问题，我们培养了一种温度敏感（ts）突变的噬菌体 D29，它可以在 37°C 下生长，但不能在 42°C 下生长，并利用它进行差异基因表达和蛋白质组分析研究。我们的分析结果表明，当温度从 37°C 升高到 42°C 时，位于右臂的被认为是早期表达的基因的表达水平降低。相比之下，位于左臂的晚期基因的表达仅受到轻微影响。因此，我们得出结论，两条臂上的基因转录是相互独立的，并且必须有一个特定的因素来控制右臂基因的表达。我们还观察到，在右臂本身内部；存在一种机制来确保胸腺嘧啶核苷合成酶 X 的 Gp48 的高水平合成。这种蛋白质在感染细胞中的高表达导致延迟裂解和更高的噬菌体产量。
