Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany.
mBio. 2019 Mar 5;10(2):e02492-18. doi: 10.1128/mBio.02492-18.
Cyclic dinucleotides (cDNs) act as intracellular second messengers, modulating bacterial physiology to regulate the fundamental life style transition between motility and sessility commonly known as biofilm formation. Cyclic GMP-AMP (cGAMP), synthesized by the dinucleotide cyclase DncV, is a newly discovered cDN second messenger involved in virulence and chemotaxis in O1 biovar El Tor. Here we report a novel role for horizontally transferred DncV in cGAMP production and regulation of biofilm formation and motility in the animal commensal strain ECOR31. ECOR31 expresses a semiconstitutive temperature-independent rdar (ed, ry, nd ough) morphotype on Congo red agar plates characterized by the extracellular matrix components cellulose and curli fimbriae which requires activation by the major biofilm regulator CsgD and cyclic di-GMP signaling. In contrast, C-terminal His-tagged DncV negatively regulates the rdar biofilm morphotype and cell aggregation via downregulation of mRNA steady-state level. Furthermore, DncV sequentially promotes and inhibits adhesion to the abiotic surface after 24 h and 48 h of growth, respectively. DncV also suppresses swimming and swarming motility posttranscriptional of the class 1 flagellum regulon gene Purified DncV produced different cDNs, cyclic di-GMP, cyclic di-AMP, an unknown product(s), and the dominant species 3'3'-cGAMP. , only the 3'3'-cGAMP concentration was elevated upon short-term overexpression of , making this work a first report on cGAMP production in Regulation of rdar biofilm formation and motility upon overexpression of untagged DncV in combination with three adjacent cotransferred gene products suggests a novel temperature-dependent cGAMP signaling module in ECOR31. The ability of bacteria to sense and respond to environmental signals is critical for survival. Bacteria use cyclic dinucleotides as second messengers to regulate a number of physiological processes, such as the fundamental life style transition between motility and sessility (biofilm formation). cGAMP, which is synthesized by a dinucleotide cyclase called DncV, is a newly discovered second messenger involved in virulence and chemotaxis in the biovar El Tor causing the current 7th cholera pandemic. However, to what extent cGAMP exists and participates in physiological processes in other bacteria is still unknown. In this study, we found an elevated cGAMP level to possibly regulate biofilm formation and motility in the animal commensal strain ECOR31. Thus, we detected a novel role for cGAMP signaling in regulation of physiological processes other than those previously reported in proteobacterial species.
环二核苷酸（cDNs）作为细胞内的第二信使，调节细菌生理学，从而调节通常被称为生物膜形成的运动性和静止性之间的基本生活方式转变。由二核苷酸环化酶 DncV 合成的环鸟苷一磷酸-AMP（cGAMP）是一种新发现的 cDN 第二信使，参与 O1 生物型 El Tor 霍乱弧菌的毒力和趋化性。在这里，我们报告了水平转移的 DncV 在 cGAMP 产生以及调节动物共生菌株 ECOR31 生物膜形成和运动性方面的新作用。ECOR31 在刚果红琼脂平板上表现出半组成型温度非依赖性 rdar（ed、ry、nd ough）形态，其特征是细胞外基质成分纤维素和卷曲菌毛，这需要主要生物膜调节剂 CsgD 和环二鸟苷酸信号的激活。相比之下，C 端组氨酸标记的 DncV 通过下调 mRNA 稳态水平，负调节 rdar 生物膜形态和细胞聚集。此外，DncV 在生长 24 小时和 48 小时后分别促进和抑制对非生物表面的粘附。DncV 还抑制类 1 鞭毛调控基因 Purified DncV 产生不同的 cDN、环二鸟苷酸、环二腺苷酸、未知产物和主要物种 3'3'-cGAMP。只有在短时间过表达 时，3'3'-cGAMP 的浓度升高，这是首次报道在 Regulation of rdar biofilm formation and motility upon overexpression of untagged DncV in combination with three adjacent cotransferred gene products suggests a novel temperature-dependent cGAMP signaling module in ECOR31. The ability of bacteria to sense and respond to environmental signals is critical for survival. Bacteria use cyclic dinucleotides as second messengers to regulate a number of physiological processes, such as the fundamental life style transition between motility and sessility (biofilm formation). cGAMP, which is synthesized by a dinucleotide cyclase called DncV, is a newly discovered second messenger involved in virulence and chemotaxis in the biovar El Tor causing the current 7th cholera pandemic. However, to what extent cGAMP exists and participates in physiological processes in other bacteria is still unknown. In this study, we found an elevated cGAMP level to possibly regulate biofilm formation and motility in the animal commensal strain ECOR31. Thus, we detected a novel role for cGAMP signaling in regulation of physiological processes other than those previously reported in proteobacterial species.
