Project description:Although the ubiquitous bacterial secondary messenger cyclic diguanylate (c-di-GMP) plays important roles in various cellular functions including the formation of biofilm in a wide range of bacteria, its function in model plant pathogen Pseudomonas syringae is largely elusive. In order to test this in P. syringae, we overexpressed a diguanylate cyclase (YedQ) and a phosphodiesterase (YhjH) that are originally from Escherichia coli, resulting in high and low c-di-GMP levels in P. syringae, respectively. Through performing genome-wide RNA sequencing of these two strains, we found that c-di-GMP regulates (i) fliN, fliE and flhA genes, which are associated with flagellar assembly, (ii) alg8 and alg44, which are related to exopolysaccaride biosynthesis pathway, (iii) pvdE, pvdP and pvsA genes, related to siderophore biosynthesis pathway, and (iv) sodA, which is a superoxide dismutase. In particular, we identified five genes sensitive to elevated c-di-GMP level and constructed five luciferase-based reporters that effectively respond to intracellular level of c-di-GMP in P. syringae, which can be used to measure c-di-GMP levels in vivo in the future. Based on the RNA-seq results, phenotypic assays confirmed that c-di-GMP regulated many important biological pathways in P. syringae, such as negative regulation of type III secretion system (T3SS) and motility as well as positive regulation of EPS production, siderophore production and oxidative stress resistance. Taken together, the present study demonstrated that c-di-GMP is closely related to virulence and stress response in P. syringae, suggesting that tuning its level can be a new strategy to protect plants from the attack of this pathogen in the future.
Project description:The profiles of transcripts from the V. vulnificus grown under normal and high c-di-GMP conditions were compared by using a V. vulnificus whole-genome microarray Two-condition experiment, normal c-di-GMP condition vs. high c-di-GMP condition. Biological replicates: 3 control, 3 experimental, independently grown and harvested. One replicate per array. For transcriptome analysis, the V. vulnificus whole genome TwinChip, manufactured and kindly provided by the 21C Frontier Microbial Genomics and Applications Center (Daejeon, South Korea), was used.
Project description:The second messenger c-di-GMP has important functions in response to changing environmental and cellular cues in bacteria. Here, we report the identification of CdbA, a DNA binding protein of the ribbon-helix-helix family in Myxococcus xanthus, and show that it binds c-di-GMP in vitro. CdbA is essential for viability and its depletion caused defects in chromosome organization and segregation resulting in a block in cell division. CdbA binds multiple sites across the M. xanthus genome with moderate sequence specificity; however, its depletion only caused minor changes in transcription. C-di-GMP binding and DNA binding by CdbA are mutually exclusive and substitutions in the CdbA interfaces important for c-di-GMP binding not only abolished c-di-GMP binding but also DNA binding and rendered the mutant proteins non-functional in vivo. Our data are consistent with a model whereby CdbA functions as a nucleoid associated protein to organize the M. xanthus chromosome and the function of CdbA is modulated by c-di-GMP, thus, for the first time, establishing a link between c-di-GMP and chromosome organization and segregation.
Project description:The profiles of transcripts from the V. vulnificus grown under normal and high c-di-GMP conditions were compared by using a V. vulnificus whole-genome microarray
Project description:Sinorhizobium meliloti is a soil-dwelling symbiotic alphaproteobacterium. Cyclic di-GMP is an important second messenger controlling multiple functions in this microorganism. To understand transcriptional regulation by elevated c-di-GMP in S. meliloti, the transcriptome analysis was performed on the wild type strain S. meliloti Rm2011 carrying either an empty vector pWBT or diguanylate cyclase gene pleD overexpression plasmid pWBT-pleD.
Project description:The cyanobacterial phytochrome Cph2 is a light-dependent diguanylate cyclase producing the second messenger c-di-GMP. Under blue light, the Cph2-dependent increase in the cellular c-di-GMP concentration leads to inhibition of motility in the cyanobacterium Synechocystis 6803. However, the targets of c-di-GMP in this cyanobacterium and its mechanism of action remained unclear. Here, we determined the cellular concentrations of three cyclic nucleotides in wild-type and Δcph2 cells after blue- and green light illumination. Inactivation of the photoreceptor gene completely abolished the blue-light dependent increase in the c-di-GMP content. Microarray analysis revealed that in the wild type in comparison to the Δcph2 mutant, blue light mainly led to a change in accumulation of mRNAs encoding minor pilins, putative chaperone usher pili as well as several chemotaxis regulators. The mRNA encoding the minor pilins pilA5-pilA6 is negatively affected by high c-di GMP content under blue light, whereas the minor pilin encoding operon pilA9-slr2018 accumulates under the same conditions, suggesting opposing functions of the respective gene sets. Based on mutational and gene expression analysis, we further suggest that the second Synechocystis 6803 homolog of a CRP-like transcription factor, SyCRP2, is the regulator of minor pilin gene expression and of putative chaperone usher pili genes slr1667/slr1668. Thus, our work indicates that the Cph2-mediated increase in cellular c-di-GMP concentration upon blue-light illumination specifically changes the transcriptome of Synechocystis 6803.
Project description:Upon systemic bacterial infection, hematopoietic stem and progenitor cells (HSPCs) migrate to the periphery in order to supply a sufficient number of immune cells. Although pathogen-associated molecular patterns (PAMPs) reportedly mediate HSPC activation, how HSPCs detect pathogen invasion in vivo remains elusive. Bacteria use the second messenger bis-(3’-5’)-cyclic dimeric guanosine monophosphate (c-di-GMP) for a variety of activities. Here we report that c-di-GMP comprehensively regulates both HSPCs and their niche cells through an innate immune sensor, STING, thereby inducing entry into the cell cycle and mobilization of HSPCs, while decreasing the number and repopulation capacity of long-term hematopoietic stem cells (LT-HSCs). Furthermore, we show that type I IFN acts as a downstream target of c-di-GMP to inhibit HSPC expansion in the spleen, while TGF-β1 is required for c-di-GMP-dependent splenic HSPC expansion. Our results define novel machinery underlying dynamic regulation of HSPCs and their niches during bacterial infection through c-di-GMP/STING signaling. Ten-week-old mice were intraperitoneally administered PBS or 200 nmol c-di-GMP, and CD150+ CD41- CD48- CD34- Flt3- LSK cells of pooled bone marrow from 10 mice per group were sorted 3 days later. mRNA was then extracted using RNeasy micro (Qiagen). Likewise, CD45- Ter-119- CD31- CD140a+ CD51+ MSCs and CD45- Ter119- CD31+ endothelial cells from c-di-GMP-treated or untreated mice were sorted and mRNA was extracted. cDNA was synthesized from mRNA and hybridized to gene chip Mouse60k (Agilent Technologies) and expression levels analyzed.
Project description:Cyclic di-GMP (c-di-GMP) is a ubiquitous second messenger that regulates many biological processes in bacteria. The genome in Mycobacterium tuberculosis encodes a single copy of the diguanylate cyclase gene (dgc) responsible for c-di-GMP synthesis. To determine the role of c-di-GMP signaling in M. tuberculosis, the mutant strain of Δdgc was generated in the virulent H37Rv strain. We used whole genome microarray expression profiling as a discovery platform to identify the genes controlled by c-di-GMP in M. tuberculosis, providing molecular proof for the phenotypes modulated by the signaling.
Project description:Cyclic di-GMP (c-di-GMP) is a ubiquitous second messenger that regulates many biological processes in bacteria. The genome in Mycobacterium tuberculosis encodes a single copy of the diguanylate cyclase gene (dgc) responsible for c-di-GMP synthesis. To determine the role of c-di-GMP signaling in M. tuberculosis, the mutant strain of Δdgc was generated in the virulent H37Rv strain. We used whole genome microarray expression profiling as a discovery platform to identify the genes controlled by c-di-GMP in M. tuberculosis, providing molecular proof for the phenotypes modulated by the signaling. Wild-type H37Rv and Δdgc cultures were analyzed under aerobic conditions or in an in vitro dormancy model. Bacteria were collected at OD600 =1.3 for the aerobic cultures and upon the beginning of anaerobiosis for the cultures in the dormancy model. One culture for each experiment was assayed except for Δdgc under anaerobiosis (2 independent cultures).