Sloup Rudolph E, Konal Ashley E, Severin Geoffrey B, Korir Michelle L, Bagdasarian Mira M, Bagdasarian Michael, Waters Christopher M
Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA.
Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
J Bacteriol. 2017 Sep 5;199(19). doi: 10.1128/JB.00106-17. Print 2017 Oct 1.
is a human pathogen that alternates between growth in environmental reservoirs and infection of human hosts, causing severe diarrhea. The second messenger cyclic di-GMP (c-di-GMP) mediates this transition by controlling a wide range of functions, such as biofilms, virulence, and motility. Here, we report that c-di-GMP induces expression of the extracellular protein secretion () gene cluster, which encodes the type II secretion system (T2SS) in Analysis of the genes confirmed the presence of two promoters located upstream of , the first gene in the operon, one of which is induced by c-di-GMP. This induction is directly mediated by the c-di-GMP-binding transcriptional activator VpsR. Increased expression of the operon did not impact secretion of extracellular toxin or biofilm formation but did increase expression of the pseudopilin protein EpsG on the cell surface. Type II secretion systems (T2SSs) are the primary molecular machines by which Gram-negative bacteria secrete proteins and protein complexes that are folded and assembled in the periplasm. The substrates of T2SSs include extracellular factors, such as proteases and toxins. Here, we show that the widely conserved second messenger cyclic di-GMP (c-di-GMP) upregulates expression of the genes encoding the T2SS in the pathogen via the c-di-GMP-dependent transcription factor VpsR.
是一种人类病原体，在环境储库中的生长与人类宿主的感染之间交替，导致严重腹泻。第二信使环二鸟苷酸（c-di-GMP）通过控制多种功能，如生物膜、毒力和运动性，介导这种转变。在这里，我们报告c-di-GMP诱导细胞外蛋白分泌（）基因簇的表达，该基因簇在中编码II型分泌系统（T2SS）。对基因的分析证实，在操纵子的第一个基因上游存在两个启动子，其中一个由c-di-GMP诱导。这种诱导直接由c-di-GMP结合转录激活因子VpsR介导。操纵子表达的增加对细胞外毒素的分泌或生物膜形成没有影响，但确实增加了细胞表面假菌毛蛋白EpsG的表达。II型分泌系统（T2SSs）是革兰氏阴性菌分泌在外周质中折叠和组装的蛋白质和蛋白质复合物的主要分子机器。T2SSs的底物包括细胞外因子，如蛋白酶和毒素。在这里，我们表明，广泛保守的第二信使环二鸟苷酸（c-di-GMP）通过c-di-GMP依赖性转录因子VpsR上调病原体中编码T2SS的基因的表达。
