Inefficient translation of nsrR constrains behavior of the NsrR regulon in Escherichia coli
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ABSTRACT: Investigation of whole genome gene expression level changes in a Escherichia coli MG1655 K-12 nsrR with AUG start codon compared to the wild type nsrR (with a GUG start codon) and to the control lacking the nsrR gene. Conversion of the nsrR start codon from the wild type GUG to AUG increased the efficiency of translation and had measurable effects on the expression patterns of some NsrR regulated genes. A nine chip study using total RNA recovered from three separate cultures of Escherichia coli MG1655 K-12 AUGnsrR, three separate cultures of the WT nsrR (GUGnsrR) and three separate cultures of nsrR deletion strain. Each chip measures the expression level of 4,254 genes from Escherichia coli MG1655 K-12 with eight 60-mer probes per gene, with 2-fold technical redundancy.
ORGANISM(S): Escherichia coli str. K-12 substr. MG1655
Project description:Investigation of whole genome gene expression level changes in a Escherichia coli MG1655 K-12 nsrR with AUG start codon compared to the wild type nsrR (with a GUG start codon) and to the control lacking the nsrR gene. Conversion of the nsrR start codon from the wild type GUG to AUG increased the efficiency of translation and had measurable effects on the expression patterns of some NsrR regulated genes.
Project description:NsrR is a nitric oxide sensitive regulator of transcription. In Escherichia coli, NsrR is a repressor of the hmp gene encoding the flavohemoglobin that detoxifies nitric oxide. Several other transcription units (including ytfE, ygbA and hcp-hcr) are known to be subject to regulation by NsrR. In this study, chromatin immunoprecipitation and microarray analysis was used to identify NsrR binding sites in the chromosome of Escherichia coli strain MG1655. Keywords: ChIP-chip
Project description:Investigation of whole genome gene expression level changes in a Escherichia coli MG1655 K-12 M-bM-^HM-^FarcA mutant, compared to the wild-type strain. The mutations engineered into this strain produce a strain lacking the ArcA protein. The results are further described in the manuscript The response regulator ArcA uses a diverse binding site architechture to globally regulate carbon oxidation in E. coli A six chip study using total RNA recovered from three separate cultures of Escherichia coli MG1655 K-12 WT and three separate cultures of the M-bM-^HM-^FarcA mutant strain. Each chip measures the expression level of 4,661 genes from Escherichia coli MG1655 K-12 with eight 60-mer probes per gene, with each probe represented twice on the array.
Project description:Investigation of whole genome gene expression level changes in a Escherichia coli MG1655 K-12 ?fnr mutant, compared to the wild-type strain. The mutations engineered into this strain produce a strain lacking the FNR protein. WT strains were grown under aerobic and anaerobic growth conditions. A six chip study using total RNA recovered from two separate cultures of Escherichia coli MG1655 K-12 WT (aerobic and anaerobic) and two separate cultures of the ?fnr mutant strain (anaerobic). Each chip measures the expression level of 4,661 genes from Escherichia coli MG1655 K-12 with eight 60-mer probes per gene, with each probe represented twice on the array.
Project description:This SuperSeries is composed of the following subset Series: GSE35746: Comparative analysis of regulatory elements between Escherichia coli and Klebsiella pneumoniae by genome-wide transcription start site profiling [tiling arrays] GSE35821: Comparative analysis of regulatory elements between Escherichia coli and Klebsiella pneumoniae by genome-wide transcription start site profiling [TSS-Seq] Refer to individual Series
Project description:Investigation of whole genome gene expression level in E. coli K-12 MG1655 in glucose M9 minimal media with/without heatshock A six chip study using total RNA recovered from E. coli K-12 MG1655 grown up to OD600nm 0.6 (mid-exponential phase) in M9 minimal media supplemented with 0.2% glucose with/without heatshock in 42oC. The high-density oligonucleotide tiling arrays used were consisted of 371,034 oligonucleotide probes with 50-bp length that are spaced 25 bp apart across the E. coli genome (NimbleGen). Experiments were performed with three biological replicates.
Project description:To fit within the confines of the cell, bacterial chromosomes are highly condensed into a structure called the nucleoid. Despite the high degree of compaction in the nucleoid, the genome remains accessible to essential biological processes, such as replication and transcription. Here, we present the first high-resolution chromosome conformation capture-based molecular analysis of the spatial organization of the Escherichia coli nucleoid during rapid growth in rich medium and following an induced amino acid starvation that promotes the stringent response. Our analyses identify the presence of origin and terminus domains in exponentially growing cells. Moreover, we observe an increased number of interactions within the origin domain and significant clustering of SeqA-binding sequences, suggesting a role for SeqA in clustering of newly replicated chromosomes. By contrast, ‘histone-like’ protein (i.e. Fis, IHF and H-NS) binding sites did not cluster, and their role in global nucleoid organization does not manifest through the mediation of chromosomal contacts. Finally, genes that were downregulated after induction of the stringent response were spatially clustered, indicating that transcription in E. coli occurs at transcription foci. A 4 chips study of exponentially growing wild type E. coli strain MG1655 grown in LB rich media or after induction of the stringent response by serine hydroxamate for 30 min. Two technical replicates, Three biological replicates mixed prior hybridization on the chip.
Project description:Investigation of whole genome gene expression level changes in a Escherichia coli MG1655 K-12 M-bM-^HM-^Fhns/M-bM-^HM-^FstpA strain from exponental growth under aerobic and anaerobic growth conditions. The results are further described in the article Genome-scale Analysis of E.coli FNR Reveals the Complex Features of Transcrtipion Factor Binding. A four chip study using total RNA recovered from two separate cultures of Escherichia coli MG1655 K-12 M-bM-^HM-^Fhns/M-bM-^HM-^FstpA mutant strain under aerobic and anaerobic growth conditions. Each chip measures the expression level of 4,661 genes from Escherichia coli MG1655 K-12 using a high-density tiling array consisting of ~385,000 60mer probes spaced every 12 bp.
Project description:We applied ChIP-seq to identify genome wide binding targets of NsrR in E.coli CFT073. NsrR is a nitric oxide sensitive regulator of transcription. Genome wide binding targets of NsrR have been identified in E.coli K12 using ChIP-chip. The genome of CFT073 is about 0.6Mb larger than that of K12. In this study, we identify the novel NsrR binding sites in CFT073.
Project description:Aberrant translation initiation at non-AUG start codons is associated with multiple cancers and neurodegenerative diseases. Nevertheless, how non-AUG translation is regulated differently from canonical translation is poorly understood. We thus used start codon-selective reporters and ribosome profiling to characterize how translation from non-AUG start codons responds to protein synthesis inhibitors in human cells. These analyses surprisingly revealed that translation of non-AUG reporters and the endogenous GUG-encoded DAP5 (eIF4G2/p97) mRNA are resistant to cycloheximide (CHX), a translation inhibitor which slows but does not completely abrogate elongation. Our data suggest that slowly elongating ribosomes cause queuing of scanning pre-initiation complexes (PIC), preferentially enhancing otherwise poor recognition of non-AUG start codons. Consistent with this model, limiting PIC formation or scanning sensitizes non-AUG translation to CHX. Moreover, PIC queuing can cause translation from an AUG codon in a poor context to become less sensitive to CHX. We further find that non-AUG translation is resistant to other inhibitors that target ribosomes within the coding sequence, but not those targeting newly initiated ribosomes. In total, these data indicate that ribosome queuing enables mRNAs with poor initiation context, namely those from non-AUG start codons, to be resistant to pharmacological inhibitors.