Peters Ryan G, Kelly Jessica M, Bibeau Sarah, Zhou Ying, Shell Scarlet S
Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01609, USA.
Pathogens. 2024 Nov 27;13(12):1041. doi: 10.3390/pathogens13121041.
The ESX-1 secretion system is critical for the virulence of as well as for conjugation in the saprophytic model . EsxB (CFP-10) and EsxA (ESAT-6) are secreted effectors required for the function of ESX-1 systems. While some transcription factors regulating the expression of and have been identified, little work has addressed their promoter structures or other determinants of their expression. Here, we defined two promoters, one located two genes upstream of and one located immediately upstream, that contribute substantially to the expression of and . We also defined an mRNA cleavage site within the 5' untranslated region (UTR) and found that a single-nucleotide substitution reprogramed the position of this cleavage event without impacting - transcript abundance. We furthermore investigated the impact of a double stem-loop structure in the 5' UTR and found that it does not confer stability on a reporter gene transcript. Consistent with this, there was no detectable correlation between mRNA half-life and secondary structure near the 5' ends of 5' UTRs on a transcriptome-wide basis. Collectively, these data shed light on the determinants of expression in as well as provide broader insight into the determinants of mRNA cleavage in mycobacteria and the relationship between 5' UTR secondary structure and mRNA stability.
ESX-1分泌系统对于在腐生模型中的毒力以及接合作用至关重要。EsxB（CFP-10）和EsxA（ESAT-6）是ESX-1系统功能所需的分泌效应物。虽然已经鉴定出一些调节和表达的转录因子，但很少有研究涉及其启动子结构或其他表达决定因素。在这里，我们定义了两个启动子，一个位于上游两个基因处，另一个位于紧邻上游，它们对和的表达有很大贡献。我们还在5'非翻译区（UTR）内定义了一个mRNA切割位点，发现单核苷酸取代重新编程了该切割事件的位置，而不影响转录本丰度。我们进一步研究了5'UTR中双茎环结构的影响，发现它不会赋予报告基因转录本稳定性。与此一致，在全转录组范围内，mRNA半衰期与5'UTR 5'端附近的二级结构之间没有可检测到的相关性。这些数据共同揭示了表达的决定因素，同时也为分枝杆菌中mRNA切割的决定因素以及5'UTR二级结构与mRNA稳定性之间的关系提供了更广泛的见解。
