Project description:The dimerization and binding of DNA by BldD is affected by its interaction with cyclic di-GMP. The D116A mutant of BldD is partially impaired in its biding of cyclic di-GMP. ChIP-Seq was carried out to determine the difference in the degree of DNA binding by the wild type and D116A mutated BldD in Streptomyces venezuelae.
Project description:The innate immune system responds to unique molecular signatures that are widely conserved among microbes but that are not normally present in host cells. Compounds that stimulate innate immune pathways may be valuable in the design of novel adjuvants, vaccines, and other immunotherapeutics.The cyclic dinucleotide cyclic-di-guanosine monophosphate (c-di-GMP) is a recently appreciated second messenger that plays critical regulatory roles in many species of bacteria but is not produced by eukaryotic cells. In vivo and in vitro studies have previously suggested that c-di-GMP is a potent immunostimulatory compound recognized by mouse and human cells. Here we provide evidence that c-di-GMP is sensed in the cytosol of mammalian cells via a novel immunosurveillance pathway. The potency of cytosolic signaling induced by cyclic-di- GMP is comparable to that induced by cytosolic delivery of DNA, and both nucleic acids induce a similar transcriptional profile, including triggering of type I interferons and coregulated genes via induction of TBK1, IRF3, NF-!B and MAP kinases. However, the cytosolic pathway that senses c-di-GMP appears to be distinct from all known nucleic acid-sensing pathways.Our results suggest a novel mechanism by which host cells can induce an inflammatory response to a widely produced bacterial ligand. Three-condition experiment: macrophages transfected with mono-GMP (negative control), double-stranded DNA (positive control), or cyclic-di-GMP (experimental condition). Biological replicates: two, independently treated, harvested, and hybridized to arrays. One replicate per array, except two technical replicates were performed for one of the positive control samples.
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:To examine the effects of cyclic-di-GMP on DNA binding by BldD in vivo, we manipulated the levels of c-di-GMP in Streptomyces venezuelae and monitored the effect on BldD binding to its target promoters in vivo by ChIP-seq, using a polyclonal BldD antibody. The degree of BldD binding was assayed at a single time point in wild-type (wt) S. venezuelae and the wt overexpressing either the diguanylate cyclase CdgB or the phosphodiesterase YhjH. A bldD null mutant was used a negative control.
Project description:The innate immune system responds to unique molecular signatures that are widely conserved among microbes but that are not normally present in host cells. Compounds that stimulate innate immune pathways may be valuable in the design of novel adjuvants, vaccines, and other immunotherapeutics.The cyclic dinucleotide cyclic-di-guanosine monophosphate (c-di-GMP) is a recently appreciated second messenger that plays critical regulatory roles in many species of bacteria but is not produced by eukaryotic cells. In vivo and in vitro studies have previously suggested that c-di-GMP is a potent immunostimulatory compound recognized by mouse and human cells. Here we provide evidence that c-di-GMP is sensed in the cytosol of mammalian cells via a novel immunosurveillance pathway. The potency of cytosolic signaling induced by cyclic-di- GMP is comparable to that induced by cytosolic delivery of DNA, and both nucleic acids induce a similar transcriptional profile, including triggering of type I interferons and coregulated genes via induction of TBK1, IRF3, NF-!B and MAP kinases. However, the cytosolic pathway that senses c-di-GMP appears to be distinct from all known nucleic acid-sensing pathways.Our results suggest a novel mechanism by which host cells can induce an inflammatory response to a widely produced bacterial ligand.
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:<p>Cyclic di-GMP (c-di-GMP) is a well-known second messenger that plays a key role in many physiological processes in bacteria. The synthesis of lipids is essential for bacterial biofilm formation. However, whether c-di-GMP signaling modulates the synthesis of lipid and further regulates biofilm formation in mycobacteria is unclear, and the c-di-GMP receptor involved remains unknown. In this study, we characterized the nucleoid-associated protein (NAP) Lsr2 as a novel c-di-GMP receptor in mycobacteria. c-di-GMP specifically binds to Lsr2 at a ratio of 1:1. We showed that c-di-GMP promotes mycobacterial biofilm formation in a manner dependent on Lsr2. Furthermore, Lsr2 mediates the synthesis of keto-mycolic acid, the lipid component of the mycobacterial cell wall, by positively regulating the expression of HadD, a (3R)-hydroxyacyl-ACP dehydratase, thus, Lsr2 ultimately controls biofilm formation. Finally, c-di-GMP promotes the positive regulation of HadD by Lsr2 and mycobacterial biofilm formation. Thus, we report a novel c-di-GMP receptor that links the second messenger’s function to lipid synthesis and biofilm formation in mycobacteria.</p>
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).
Project description:We have previously reported that Mycobacterium tuberculosis Rv2837c (cnpB) encodes a phosphodiesterase that specifically cleaves cyclic di-AMP (c-di-AMP) into AMP. Deletion of cnpB results in significant virulence attenuation in a mouse pulmonary infection model, which is very likely due to the significantly elevated c-di-AMP levels as overexpression of Mtb diadenylate cyclase, disA, also leads to a similar outcome. An earlier study also demonstrated that CnpB functions similarly to E. coli oligoribonuclease (Orn) that hydrolyzes 2-5-mer nanoRNAs (short oligonucleotides of five residues or shorter in length) except that CnpB prefers 2-mer nanoRNA as a substrate. Additionally, a recent report showed that CnpB also degrades cyclic di-GMP (c-di-GMP), although we demonstrated that CnpB prefers c-di-AMP to c-di-GMP according to an in vitro enzymatic kinetics analysis In this study, we initially attempted to determine c-di-AMP-mediated gene regulation in Mtb by comparing the expression profiles between WT and ∆cnpB using RNA-Seq. We found that the CRISPR-Cas system of M. tuberculosis was highly upregulated by deletion of cnpB.