Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, Houston, Texas, USA.
Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA.
J Bacteriol. 2019 Apr 24;201(10). doi: 10.1128/JB.00703-18. Print 2019 May 15.
Ethanolamine (EA) is a compound prevalent in the gastrointestinal (GI) tract that can be used as a carbon, nitrogen, and/or energy source. , a GI commensal and opportunistic pathogen, contains approximately 20 thanolamine ilization () genes encoding the necessary regulatory, enzymatic, and structural proteins for this process. Here, using a chemically defined medium, two regulatory factors that affect EA utilization were examined. First, the functional consequences of loss of the small RNA (sRNA) EutX on the efficacy of EA utilization were investigated. One effect observed, as loss of this negative regulator causes an increase in gene expression, was a concomitant increase in the number of catabolic acterial icroompartments (BMCs) formed. However, despite this increase, the growth of the strain was repressed, suggesting that the overall efficacy of EA utilization was negatively affected. Second, utilizing a deletion mutant and a complement, carbon catabolite control protein A (CcpA) was shown to be responsible for the repression of EA utilization in the presence of glucose. A predicted site in one of the three EA-inducible promoters, , was identified as the target of CcpA. However, CcpA was shown to affect the activation of all the promoters indirectly through the two-component system EutV and EutW, whose genes are under the control of the promoter. Moreover, a bioinformatics analysis of bacteria predicted to contain CcpA and sites revealed that a preponderance of BMC-containing operons are likely regulated by carbon catabolite repression (CCR). Ethanolamine (EA) is a compound commonly found in the gastrointestinal (GI) tract that can affect the behavior of human pathogens that can sense and utilize it, such as and Therefore, it is important to understand how the genes that govern EA utilization are regulated. In this work, we investigated two regulatory factors that control this process. One factor, a small RNA (sRNA), is shown to be important for generating the right levels of gene expression for maximum efficiency. The second factor, a transcriptional repressor, is important for preventing expression when other preferred sources of energy are available. Furthermore, a global bioinformatics analysis revealed that this second mechanism of transcriptional regulation likely operates on similar genes in related bacteria.
乙醇胺（EA）是一种在胃肠道（GI）中普遍存在的化合物，可以用作碳、氮和/或能源。作为 GI 共生菌和机会性病原体，它含有大约 20 个乙醇胺利用（）基因，这些基因编码该过程所需的调节、酶和结构蛋白。在这里，使用化学定义的培养基，研究了影响 EA 利用的两个调节因子。首先，研究了小 RNA（sRNA）EutX 缺失对 EA 利用效率的功能后果。观察到的一个影响是，由于这种负调节剂的丧失导致基因表达增加，同时形成的分解代谢细菌微区室（BMC）的数量增加。然而，尽管有这种增加，菌株的生长受到抑制，表明 EA 利用的整体效率受到负面影响。其次，利用缺失突变体和互补体，发现碳分解代谢物控制蛋白 A（CcpA）负责在存在葡萄糖的情况下抑制 EA 利用。在三个 EA 诱导启动子之一中，鉴定出一个预测的 CcpA 位点作为靶标。然而，通过双组分系统 EutV 和 EutW，发现 CcpA 间接地影响所有启动子的激活，EutV 和 EutW 的基因受启动子的控制。此外，对预测含有 CcpA 和 位点的细菌进行生物信息学分析表明，大多数包含 BMC 的操纵子可能受到碳分解代谢物抑制（CCR）的调节。乙醇胺（EA）是一种在胃肠道（GI）中常见的化合物，它可以影响能够感知和利用它的人类病原体的行为，如 和 。因此，了解控制 EA 利用的基因如何调节是很重要的。在这项工作中，我们研究了控制这一过程的两个调节因子。一种因子，小 RNA（sRNA），对于产生最大效率所需的正确基因表达水平是很重要的。第二种因子，一种转录抑制剂，对于在有其他首选能量来源时防止表达是很重要的。此外，一项全球生物信息学分析显示，这种转录调节的第二种机制可能在相关细菌的类似基因上运作。
