Project description:BACKGROUND: Nitrogen is an essential element for bacterial growth and an important component of biological macromolecules. Consequently, responding to nitrogen limitation is critical for bacterial survival and involves the interplay of signalling pathways and transcriptional regulation of nitrogen assimilation and scavenging genes. In the soil dwelling saprophyte Mycobacterium smegmatis the OmpR-type response regulator GlnR is thought to mediate the transcriptomic response to nitrogen limitation. However, to date only ten genes have been shown to be in the GlnR regulon, a vastly reduced number compared to other organisms. RESULTS: We investigated the role of GlnR in the nitrogen limitation response and determined the entire GlnR regulon, by combining expression profiling of M. smegmatis wild type and glnR deletion mutant, with GlnR-specific chromatin immunoprecipitation and high throughput sequencing. We identify 53 GlnR binding sites during nitrogen limitation that control the expression of over 100 genes, demonstrating that GlnR is the regulator controlling the assimilation and utilisation of nitrogen. We also determine a consensus GlnR binding motif and identify key residues within the motif that are required for specific GlnR binding. CONCLUSIONS: We have demonstrated that GlnR is the global nitrogen response regulator in M. smegmatis, directly regulating the expression of more than 100 genes. GlnR controls key nitrogen stress survival processes including primary nitrogen metabolism pathways, the ability to utilise nitrate and urea as alternative nitrogen sources, and the potential to use cellular components to provide a source of ammonium. These studies further our understanding of how mycobacteria survive nutrient limiting conditions. [Data is also available from http://bugs.sgul.ac.uk/E-BUGS-143]
Project description:M. smegmatis wild type and glnR deletion strains grown in nitrogen limiting conditions (1 mM ammonium sulphate nitrogen source). Samples taken 1 hour after nitrogen depletion from the media for each strain.
Project description:In this approach, changes in total transcript of a glnR deletion strain of Mycobacterium smegmatis due to nitrogen starvation were monitored. This is a control experiment for the comparison of wild type and glnR deletion strain resulting in putative nitrogen-related genes which are not controlled by GlnR.
Project description:In this approach, total transcript of the Mycobacterium smegmatis wild type SMR5 and a glnR deletion strain was compared under nitrogen starvation. Transcript levels of 6 genes were enhanced, 125 genes reduced in the mutant strain. This experiment confirmed GlnR as the global regulator of nitrogen metabolism in M. smegmatis. Two biological replicates were analyzed.
Project description:Total transcriptome analyses were carried out to investigate changes in transcript patterns in the Mycobacterium smegmatis wild type strain SMR5 due to nitrogen starvation and to expand the knowledge about the role of the two transcriptional regulators of nitrogen metabolism, namely GlnR and AmtR, in these processes. A first experiment revealed enhanced transcript levels of 284 genes and reduced transcripts of 231 genes in the wild type under nitrogen starvation compared to nitrogen surplus. When glnR deletion strain MH1 was compared to the wild type under nitrogen starvation, decreased transcript levels of 125 genes were detected, indicating that these are activated by GlnR due to nitrogen limitation. Comparing amtR deletion strain YL1 to the wild type under nitrogen starvation, enhanced transcript levels of 2 genes were found, indicating that they are repressed by AmtR under nitrogen surplus. A comparison of YL1 and wild type under surplus, as well as a comparison of YL1 under nitrogen surplus and starvation and of MH1 under nitrogen surplus and starvation were carried out as additional control experiments. It can be concluded that GlnR is the master regulator of nitrogen control in M. smegmatis and that AmtR fulfills only a small, subordinate role in the regulation of an operon. This SuperSeries is composed of the following subset Series: GSE30033: Mycobacterium smegmatis - Comparison of glnR deletion strain MH1 under nitrogen surplus and starvation GSE30231: Mycobacterium smegmatis - Comparison of wild type SMR5 and amtR deletion strain YL1 under nitrogen starvation GSE30232: Mycobacterium smegmatis - Comparison of amtR deletion strain YL1 under nitrogen surplus and starvation GSE30233: Mycobacterium smegmatis - Comparison of wild type SMR5 under nitrogen surplus and starvation GSE30234: Mycobacterium smegmatis - Comparison of wild type SMR5 and glnR deletion strain MH1 under nitrogen starvation GSE30235: Mycobacterium smegmatis - Comparison of wild type SMR5 and amtR deletion strain YL1 under nitrogen surplus Refer to individual Series
Project description:Mycobacterium smegmatis SigF is a group III sigma factor. Its ortholog in M. tuberculosis is reported to have role in regulation and function of cell wall components. In present study we have created an M. smegmatis ΔsigF mutant by allele exchange method. M. smegmatis sigF mutant shows non pigmented phenotype and is more sensitive to hydrogen peroxide generated oxidative stress. DNA microarray analysis of M. smegmatis wild type and ΔsigF mutant suggests that SigF in this species controls the expression of several energy and central intermediary metabolism genes along with regulation of carotenoid biosynthesis.
Project description:In this approach, changes in total transcript of a glnR deletion strain of Mycobacterium smegmatis due to nitrogen starvation were monitored. This is a control experiment for the comparison of wild type and glnR deletion strain resulting in putative nitrogen-related genes which are not controlled by GlnR. Two biological replicates were analyzed.
Project description:In this approach, total transcript of the Mycobacterium smegmatis wild type SMR5 and a glnR deletion strain was compared under nitrogen starvation. Transcript levels of 6 genes were enhanced, 125 genes reduced in the mutant strain. This experiment confirmed GlnR as the global regulator of nitrogen metabolism in M. smegmatis. Two biological replicates were analyzed. Nadja,Jessberger
Project description:To identify the AmtR regulon of Mycobacterium smegmatis, we created a markerless deletion of the amtR gene in the background of strain M. smegmatis mc2155 (wild-type) and compared the transcription profile of both strains grown in batch culture under aerobic conditions on Hartmans de Bont medium supplemented with glycerol (carbon source) and lysine (sole nitrogen source) using microarray. Cells were harvested in early exponential growth stage.
Project description:This SuperSeries is composed of the following subset Series: GSE34919: Genome-wide Definition of the SigF Regulon in Mycobacterium tuberculosis (ChIP-chip) GSE34922: Genome-wide Definition of the SigF Regulon in Mycobacterium tuberculosis (Expression) Refer to individual Series