Project description:This SuperSeries is composed of the following subset Series: GSE33241: Novel targets of the CbrAB/Crc carbon catabolite control system revealed by transcript abundance in Pseudomonas aeruginosa [BSM] GSE33244: Novel targets of the CbrAB/Crc carbon catabolite control system revealed by transcript abundance in Pseudomonas aeruginosa [LB] Refer to individual Series
Project description:The opportunistic human pathogen Pseudomonas aeruginosa can utilize several carbon and nitrogen compounds as energy sources, which allows the bacterium to grow on a variety of different environments. Nevertheless, the uptake and utilization of these compounds is organized in a hierarchical manner, which is guaranteed by a mechanism named catabolite repression. In P. aeruginosa catabolite repression is a post-transcriptional process with the translational repressor protein, Crc, as the main component. Crc recognizes CA-motifs (acronym for catabolite activity) present in the vicinity of the ribosome binfing site of corresponding target mRNAs and therefore compete with ribosome binding. Certain conditions, which are mainly related to changes in the carbon to nitrogen ratio, induce the two component system CbrAB, which activates the transcription of the sRNA CrcZ. The sRNA sequesters Crc and allows the translation of the target mRNAs. The main focus of this study was to identify novel direct targets of the CbrAB/Crc system with the use of a transcriptome analysis in combination with the search for CA-motifs. We were able to identify five novel targets (estA, acsA, dctP, bkdR and aroP2), which were involved in the uptake and utilization of less preferred carbon sources and amino acids. Direct interaction of Crc with these genes and the resulting regulation by CbrB and CrcZ were verified using mutational analysis and in vitro and in vivo experiments. Moreover, these targets were discussed in the light of growth and biofilm development in synthetic CF sputum medium which emphasised the importance of the CbrAB/Crc system as a regulator of chronic infection.
Project description:The opportunistic human pathogen Pseudomonas aeruginosa can utilize several carbon and nitrogen compounds as energy sources, which allows the bacterium to grow on a variety of different environments. Nevertheless, the uptake and utilization of these compounds is organized in a hierarchical manner, which is guaranteed by a mechanism named catabolite repression. In P. aeruginosa catabolite repression is a post-transcriptional process with the translational repressor protein, Crc, as the main component. Crc recognizes CA-motifs (acronym for catabolite activity) present in the vicinity of the ribosome binfing site of corresponding target mRNAs and therefore compete with ribosome binding. Certain conditions, which are mainly related to changes in the carbon to nitrogen ratio, induce the two component system CbrAB, which activates the transcription of the sRNA CrcZ. The sRNA sequesters Crc and allows the translation of the target mRNAs. The main focus of this study was to identify novel direct targets of the CbrAB/Crc system with the use of a transcriptome analysis in combination with the search for CA-motifs. We were able to identify five novel targets (estA, acsA, dctP, bkdR and aroP2), which were involved in the uptake and utilization of less preferred carbon sources and amino acids. Direct interaction of Crc with these genes and the resulting regulation by CbrB and CrcZ were verified using mutational analysis and in vitro and in vivo experiments. Moreover, these targets were discussed in the light of growth and biofilm development in synthetic CF sputum medium which emphasised the importance of the CbrAB/Crc system as a regulator of chronic infection. keyword(s): genetic modification
Project description:The opportunistic human pathogen Pseudomonas aeruginosa can utilize several carbon and nitrogen compounds as energy sources, which allows the bacterium to grow on a variety of different environments. Nevertheless, the uptake and utilization of these compounds is organized in a hierarchical manner, which is guaranteed by a mechanism named catabolite repression. In P. aeruginosa catabolite repression is a post-transcriptional process with the translational repressor protein, Crc, as the main component. Crc recognizes CA-motifs (acronym for catabolite activity) present in the vicinity of the ribosome binfing site of corresponding target mRNAs and therefore compete with ribosome binding. Certain conditions, which are mainly related to changes in the carbon to nitrogen ratio, induce the two component system CbrAB, which activates the transcription of the sRNA CrcZ. The sRNA sequesters Crc and allows the translation of the target mRNAs. The main focus of this study was to identify novel direct targets of the CbrAB/Crc system with the use of a transcriptome analysis in combination with the search for CA-motifs. We were able to identify five novel targets (estA, acsA, dctP, bkdR and aroP2), which were involved in the uptake and utilization of less preferred carbon sources and amino acids. Direct interaction of Crc with these genes and the resulting regulation by CbrB and CrcZ were verified using mutational analysis and in vitro and in vivo experiments. Moreover, these targets were discussed in the light of growth and biofilm development in synthetic CF sputum medium which emphasised the importance of the CbrAB/Crc system as a regulator of chronic infection. keyword(s): genetic modification Comparative transcriptome analysis with the PAO1 wild type strain and PAO6673 (delta crc), PAO66711 (delta cbrB), PAO6679 (delta crcZ) strains grown in BSM-Succinate medium.
Project description:The opportunistic human pathogen Pseudomonas aeruginosa can utilize several carbon and nitrogen compounds as energy sources, which allows the bacterium to grow on a variety of different environments. Nevertheless, the uptake and utilization of these compounds is organized in a hierarchical manner, which is guaranteed by a mechanism named catabolite repression. In P. aeruginosa catabolite repression is a post-transcriptional process with the translational repressor protein, Crc, as the main component. Crc recognizes CA-motifs (acronym for catabolite activity) present in the vicinity of the ribosome binfing site of corresponding target mRNAs and therefore compete with ribosome binding. Certain conditions, which are mainly related to changes in the carbon to nitrogen ratio, induce the two component system CbrAB, which activates the transcription of the sRNA CrcZ. The sRNA sequesters Crc and allows the translation of the target mRNAs. The main focus of this study was to identify novel direct targets of the CbrAB/Crc system with the use of a transcriptome analysis in combination with the search for CA-motifs. We were able to identify five novel targets (estA, acsA, dctP, bkdR and aroP2), which were involved in the uptake and utilization of less preferred carbon sources and amino acids. Direct interaction of Crc with these genes and the resulting regulation by CbrB and CrcZ were verified using mutational analysis and in vitro and in vivo experiments. Moreover, these targets were discussed in the light of growth and biofilm development in synthetic CF sputum medium which emphasised the importance of the CbrAB/Crc system as a regulator of chronic infection. Comparative transcriptome analysis with the PAO1 wild type strain and PAO6673 (delta crc), PAO66711 (delta cbrB), PAO6679 (delta crcZ) strains grown in LB medium.
Project description:A transcriptomic assessment of a kinase deletion mutant (ΔpkaA) and a control strain revealed many cellular activities this kinase is impacting. Studies were conducted in the model filamentous fungi, Aspergillus nidulans¸ under rich growth conditions. PkaA is a known kinase that mediates a wide range of processes including: nutrient sensing, stress responses, regulation of metabolism, as well as development and pathogenicity. Here, fungi were grown in rich media containing glucose. The comparison between the control strain and the deletion mutant transcript levels revealed previously unknown targets, such as the transcription factor CreA, the main repressor responsible for carbon catabolite repression (CCR).
Project description:Strains of Pseudomonas putida have emerged as promising biocatalysts for the conversion of sugars and aromatics obtained from lignocellulosic biomass. Understanding the role of carbon catabolite repression (CCR) in these strains is critical to optimizing the conversion of biomass to fuels and chemicals. The functioning of CCR in a P. putida strain, P. putida M2, capable of growing on both hexose and pentose sugars as well as aromatics, was investigated by cultivation experiments, proteomics, and CRISPRi-based gene repression. Strain M2 was able to co-utilize sugars and aromatics simultaneously; however, during co-cultivation with glucose and phenylpropanoid aromatics (p-coumarate and ferulate), intermediates (4-hydroxybenzoate and vanillate) accumulated, and substrate consumption was incomplete. In contrast, xylose-aromatic consumption resulted in transient intermediate accumulation and complete aromatic consumption, while xylose was incompletely consumed. Proteomics analysis of these co- cultivations revealed that glucose exerted stronger repression compared to xylose on the proteins involved in aromatic catabolism. Key glucose (Eda) and xylose (XylX) catabolic proteins were also identified at lower abundance during co-cultivation with aromatics implying simultaneous catabolite repression by sugars and aromatics. Downregulation of crc mediated by CRISPRi led to faster growth and uptake of both glucose and p-coumarate in the CRISPRi strains compared to the control while no difference was observed on xylose + p-coumarate. The increased abundance of the Eda protein and amino acids biosynthesis proteins in the CRISPRi strain further supported these observations. Lastly, small RNAs (sRNAs) sequencing results showed that the levels of CrcY and CrcZ homologs in M2, previously identified as sRNAs involved in CCR in P. putida strains, were lower under strong CCR (glucose + p-coumarate) condition compared to when repression was absent (p-coumarate or glucose only).
Project description:The ascomycete Trichoderma reesei is one of the most well studied cellulolytic fungi and widely used in the biotechnology industry, as in the production of second-generation bioethanol. Carbon catabolite repression (CCR) mechanism adopted by T. reesei is mediated by the transcription factor CRE1 and consists in the repression of genes related to the production of cellulase when a readily available carbon source is present in the medium. Using RNA sequencing this study aims to contribute to understanding of CCR during growth in cellulose and glucose, by comparing the mutant strain of T. reesei Δcre1 with its parental, QM9414.