Genome-wide transcriptome response of Streptomyces tsukubaensis to N-acetylglucosamine
ABSTRACT: Chitin is the second most abundant biopolymer present in soils and is utilized by antibiotic-producing Streptomyces species. Its monomer, N-acetylglucosamine (NAG), regulates the developmental program of the model organism Streptomyces coelicolor. NAG blocks differentiation when growing on rich medium whilst it promotes development on poor culture media. We report here the negative effect of NAG on tacrolimus (FK506) production in Streptomyces tsukubaensis NRRL 18488 growing on a defined rich medium. Using microarrays technology, we found that GlcNAc represses the transcription of fkbN, encoding the main transcriptional activator of the tacrolimus biosynthetic cluster, and of ppt1, encoding a phosphopantheteinyltransferase involved in tacrolimus biosynthesis. On the contrary, NAG stimulated transcription of genes related to amino acid and nucleotide biosynthesis, DNA replication, RNA translation, glycolysis, pyruvate metabolism, and key gene members of the PHO regulon. The results obtained support those previously reported for S. coelicolor, but some important differences were observed Overall design: The transcriptomic experiment is composed of 16 samples from two time series named NAG (culture medium containing N-acetylglucosamine) and CTL (control condition: the culture medium without addition). Each time series was replicated once. Streptomyces tsukubaensis spores (10e9) were inoculated into 0.5-L flasks containing 100 mL of MGm-2.5 medium (PMID 22990582) and cultivated at 28 ºC, 220 rpm. Samples for RNA extraction were taken from flask cultures at 70 h, 70.5 h, 71 h and 72 h (4 timepoints × 4 cultures = 16 samples). The final concentration of N-acetylglcuosamine was 22.6 mmol/L (i. e., 0.5 % w/v).
INSTRUMENT(S): Agilent-034745 Streptomyces tsukubensis NRRL18488 microarray version 2 (StsuMIMA2)
Project description:N-acetylglucosamine, the monomer of chitin, is a favored carbon and nitrogen source for streptomycetes. Its intracellular catabolism requires the combined actions of the N-acetylglucosamine-6-phosphate (GlcNAc-6P) deacetylase NagA and the glucosamine-6-phosphate (GlcN-6P) deaminase/isomerase NagB. GlcNAc acts as a signaling molecule in the DasR-mediated nutrient sensing system, activating development and antibiotic production under poor growth conditions (famine) and blocking these processes under rich conditions (feast). In order to understand how a single nutrient can deliver opposite information according to the nutritional context, we carried out a mutational analysis of the nag metabolic genes nagA, nagB, and nagK. Here we show that the nag genes are part of the DasR regulon in Streptomyces coelicolor, which explains their transcriptional induction by GlcNAc. Most likely as the result of the intracellular accumulation of GlcN-6P, nagB deletion mutants fail to grow in the presence of GlcNAc. This toxicity can be alleviated by the additional deletion of nagA. We recently showed that in S. coelicolor, GlcNAc is internalized as GlcNAc-6P via the phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS). Considering the relevance of GlcNAc for the control of antibiotic production, improved insight into GlcNAc metabolism in Streptomyces may provide new leads toward biotechnological applications.
Project description:In this work, we identified glucose and glycerol as tacrolimus repressing carbon sources in the important species Streptomyces tsukubaensis. A genome-wide analysis of the transcriptomic response to glucose and glycerol additions was performed using microarray technology. The transcriptional time series obtained allowed us to compare the transcriptomic profiling of S. tsukubaensis growing under tacrolimus producing and non-producing conditions. The analysis revealed important and different metabolic changes after the additions and a lack of transcriptional activation of the fkb cluster. In addition, we detected important differences in the transcriptional response to glucose between S. tsukubaensis and the model species Streptomyces coelicolor. A number of genes encoding key players of morphological and biochemical differentiation were strongly and permanently downregulated by the carbon sources. Finally, we identified several genes showing transcriptional profiles highly correlated to that of the tacrolimus biosynthetic pathway regulator FkbN that might be potential candidates for the improvement of tacrolimus production Overall design: The transcriptomic experiment is composed of 54 samples from three time series named glucose, glycerol and maltose. Streptomyces tsukubaensis spores (10e9) were inoculated into 0.5-L flasks containing 100 mL of MGm-2.5 medium (PMID 22990582) and cultivated at 28 ºC, 220 rpm. Samples for RNA extraction were taken from flask cultures at 70 h, immediately before carbon source addition; then, glucose, glycerol or maltose were added and more samples were taken at 70.7 h, 72 h, 76 h, 80 h, 89 h, 92 h, 100 h, 124 h and 148 h. The final concentrations of glucose and glycerol were established at the same molarity (0.22 M; 2 % w/v and 4 % w/v for glucose and glycerol, respectively). The final concentration of maltose was 0.11 M (3 % w/v) in order to equalize the number of glucose molecules available after maltose incorporation. Each time series is composed of 2 biological replicates for 8 the first timepoints (70 h - 100 h) and 1 biological replicate for the rest of the culture time; i.e., only one culture was sampled at 124 h and 148 h. In summary, (8 timepoints × 2 replicates × 3 carbon sources) = 48 samples; (2 timepoints × 1 replicates × 3 carbon sources) = 6 samples; 48 + 6 = 54 samples in total.
Project description:We identified genome-wide binding regions of NdgR in Streptomyces coelicolor using chromatin immunoprecipitation sequencing (ChIP-seq). We constructed 6×myc-tagged NdgR strain using homologous recombination with myc-tagging vector. Analysis of the sequencing data aligned to Streptomyces coelicolor genome database (NC_003888). Overall design: 6x-myc tagged Streptomyces coelicolor M145 was cultured on solid minimal media supplemented with N-acetylglucosamine and asparagine during 36hrs. Anti-myc antibody (9E10) was used for immunoprecipitation (IP). IP-DNA was sequenced using Illumina Genome Analyzer Ⅱx
Project description:Here, we address the transcriptional response to both novobiocin-induced rapid chromosome relaxation or long-term topological imbalance, both increased and decreased supercoiling, in environmental antibiotic-producing bacteria belonging to the Streptomyces genus. Overall design: RNA was extracted from vegetative hyphae of Streptomyces coelicolor growing for 18h in liquid YEME/TSB medium (30 mL). To induce supercoiling changes S. coelicolor culture was treated with novobiocin in final concentration 10 g/ml for 10 min (rapid chromosome relaxation). For long-term exposure to topological imbalance we used PS04 stain in which TopA level is controlled by thiostrepton addition (long-term high and low DNA supercoling in not induced and induced PS04 strain, respectively)
Project description:Transcription factors (TFs) of bacterial helix-turn-helix superfamilies exhibit different effector-binding domains (EBDs) fused to a DNA-binding domain with a common feature. In a previous study of the GntR superfamily, we demonstrated that classifying members into subfamilies according to the EBD heterogeneity highlighted unsuspected and accurate TF-binding site signatures. In this work, we present how such in silico analysis can provide prediction tools to discover new cis/trans relationships. The TF-binding site consensus of the HutC/GntR subfamily was used to (i) predict target sites within the Streptomyces coelicolor genome, (ii) discover a new HutC/GntR regulon and (iii) discover its specific TF. By scanning the S.coelicolor genome we identified a presumed new HutC regulon that comprises genes of the phosphotransferase system (PTS) specific for the uptake of N-acetylglucosamine (PTS(Nag)). A weight matrix was derived from the compilation of the predicted cis-acting elements upstream of each gene of the presumed regulon. Under the assumption that TFs are often subject to autoregulation, we used this matrix to scan the upstream region of the 24 HutC-like members of S.coelicolor. orf SCO5231 (dasR) was selected as the best candidate according to the high score of a 16 bp sequence identified in its upstream region. Our prediction that DasR regulates the PTS(Nag) regulon was confirmed by in vivo and in vitro experiments. In conclusion, our in silico approach permitted to highlight the specific TF of a regulon out of the 673 orfs annotated as 'regulatory proteins' within the genome of S.coelicolor.
Project description:Streptomycetes are multicellular filamentous microorganisms, and major producers of industrial enzymes and bioactive compounds such as antibiotics and anticancer drugs. The mycelial lifestyle plays an important role in the productivity during industrial fermentations. The hyphae of liquid-grown streptomycetes can self-aggregate into pellets, which hampers their industrial exploitation. Here we show that the Mat complex, which is required for pellet formation, catalyzes the synthesis of extracellular poly-?-1,6-N-acetylglucosamine (PNAG) in the model organisms Streptomyces coelicolor and Streptomyces lividans. Extracellular accumulation of PNAG allows Streptomyces to attach to hydrophilic surfaces, while attachment to hydrophobic surfaces requires a cellulase-degradable extracellular polymer (EPS) produced by CslA. Over-expression of matAB was sufficient to restore pellet formation to cslA null mutants of S. lividans. The two EPS systems together increase the robustness of mycelial pellets. These new insights allow better control of liquid-culture morphology of streptomycetes, which may be harnessed to improve growth and industrial exploitation of these highly versatile natural product and enzyme producers.
Project description:We describe a procedure for the conjugative transfer of phage P1-derived Artificial Chromosome (PAC) library clones containing large natural product gene clusters (?70 kilobases) to Streptomyces coelicolor strains that have been engineered for improved heterologous production of natural products. This approach is demonstrated using the gene cluster for FK506 (tacrolimus), a clinically important immunosuppressant of high commercial value. The entire 83.5 kb FK506 gene cluster from Streptomyces tsukubaensis NRRL 18488 present in one 130 kb PAC clone was introduced into four different S. coelicolor derivatives and all produced FK506 and smaller amounts of the related compound FK520. FK506 yields were increased by approximately five-fold (from 1.2 mg L(-1) to 5.5 mg L(-1)) in S. coelicolor M1146 containing the FK506 PAC upon over-expression of the FK506 LuxR regulatory gene fkbN. The PAC-based gene cluster conjugation methodology described here provides a tractable means to evaluate and manipulate FK506 biosynthesis and is readily applicable to other large gene clusters encoding natural products of interest to medicine, agriculture and biotechnology.
Project description:Comparative analyses of the transcriptomes of the Streptomyces coelicolor A3(2) wild-type and the generated hbpSc-senSc-senRc (hsr) mutant under native and oxidative-stressing conditions allowed to identify differentially expressed genes, whose products may enhance the anti-oxidative defense of the bacterium. To obtain well-grown mycelia, spores of S. coelicolor (WT and hsr mutant) were inoculated in 10 ml R2 medium and grown as standing culture at 30C for 16 h and afterwards on a rotary shaker for 16 h after the addition of 90 ml R2 medium. The cultures were washed four times in minimal medium without supplement. The mycelia were suspended in 50 ml R2 medium and divided in two 25 ml-portions, one of which contained H2O2 (0.15 mM). Cultivation was continued at 30 C on a rotary shaker for two hours. Mycelia were harvested by centrifugation and the mycelia pellets were store at -80 C. Total RNA was isolated from two biological replicates. cDNA libraries of RNA from of S. coelicolor (WT and hsr mutant) were constructed using the TruSeq Stranded mRNA Library Prep Kit (Illumina,San Diego, CA, USA), and subsequently sequenced paired-end on an Illumina MiSeq system (San Diego, CA, USA) using 75 bp read length.
Project description:Transcription profiling by array using Streptomyces coelicolor oligomerics array to compare the gene expression of streptomyces lividans adpA mutant to the wild type at early stationary phase in YEME medium.
Project description:The genus Streptomyces is the best-known source of therapeutic secondary metabolites, especially antibiotics with pharmaceutical applications. Here, we performed a comparative study based on the time-resolved metabolic disparity in S. coelicolor A3(2) subjected to fermentative cultivation in two different types of media (R2YE and RSM3) in order to investigate secondary metabolite production pathways. The relative abundance of secondary metabolites, such as prodiginines, indoles, germicidins, and selected diketopiperazines, was increased in S. coelicolor A3(2) cultivated in R2YE medium compared to that in RSM3 medium, variably at the late-log and stationary phases of fermentative growth. Correlation analysis indicated that "antibiotic prodiginines" contributed maximally to the absorption maxima (A530) of culture supernatants, indicating their optimal production at 96 hours in R2YE medium. A higher abundance of L-proline (48-72 hours) followed by prodiginines (96 hours) was evident, substantiating the intertwined links between precursor and activated prodiginines pathway. Similarly, the higher abundance of indoles was concurrent with tryptophan levels in the shikimate pathway, whereas diketopiperazines were synchronously abundant along with the levels of phenylalanine, leucine, and proline. Additionally, acetyl-CoA induced the acetate pathway, resulting in the production of germicidins. Thus, our results demonstrate that S. coelicolor A3(2) produces specific secondary metabolites by enhancing the dedicated metabolic pathway responsible for their production. In conclusion, our results from this study provide insight into the metabolic pathways of S. coelicolor A3(2), and can be applied to further optimize the production of prodiginines.