scholarly journals Transcription Profiling of the Stringent Response in Escherichia coli

2007 ◽  
Vol 190 (3) ◽  
pp. 1084-1096 ◽  
Author(s):  
Tim Durfee ◽  
Anne-Marie Hansen ◽  
Huijun Zhi ◽  
Frederick R. Blattner ◽  
Ding Jun Jin
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Stress Responses ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Stringent Response ◽  
Maximum Growth ◽  
Regulatory Processes ◽  
K 12 ◽  
Encoding Genes

ABSTRACT The bacterial stringent response serves as a paradigm for understanding global regulatory processes. It can be triggered by nutrient downshifts or starvation and is characterized by a rapid RelA-dependent increase in the alarmone (p)ppGpp. One hallmark of the response is the switch from maximum-growth-promoting to biosynthesis-related gene expression. However, the global transcription patterns accompanying the stringent response in Escherichia coli have not been analyzed comprehensively. Here, we present a time series of gene expression profiles for two serine hydroxymate-treated cultures: (i) MG1655, a wild-type E. coli K-12 strain, and (ii) an isogenic relAΔ251 derivative defective in the stringent response. The stringent response in MG1655 develops in a hierarchical manner, ultimately involving almost 500 differentially expressed genes, while the relAΔ251 mutant response is both delayed and limited in scope. We show that in addition to the down-regulation of stable RNA-encoding genes, flagellar and chemotaxis gene expression is also under stringent control. Reduced transcription of these systems, as well as metabolic and transporter-encoding genes, constitutes much of the down-regulated expression pattern. Conversely, a significantly larger number of genes are up-regulated. Under the conditions used, induction of amino acid biosynthetic genes is limited to the leader sequences of attenuator-regulated operons. Instead, up-regulated genes with known functions, including both regulators (e.g., rpoE, rpoH, and rpoS) and effectors, are largely involved in stress responses. However, one-half of the up-regulated genes have unknown functions. How these results are correlated with the various effects of (p)ppGpp (in particular, RNA polymerase redistribution) is discussed.

Effect of enrofloxacin on gene expression profiles of Escherichia coli

2010 ◽  
Vol 60 (4) ◽  
pp. 653-660 ◽  
Author(s):  
Hua Bai ◽  
Wen-zheng Su ◽  
Xiao-ling Zhu ◽  
Ming Hu ◽  
Yu-qing Liu
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Expression Profiles ◽  
Gene Expression Profiles

scholarly journals In Vivo mRNA Profiling of Uropathogenic Escherichia coli from Diverse Phylogroups Reveals Common and Group-Specific Gene Expression Profiles

mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Piotr Bielecki ◽  
Uthayakumar Muthukumarasamy ◽  
Denitsa Eckweiler ◽  
Agata Bielecka ◽  
Sarah Pohl ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Specific Gene ◽  
Content Type ◽  
E Coli ◽  
Human Host ◽  
Tract Infections

ABSTRACTmRNA profiling of pathogens during the course of human infections gives detailed information on the expression levels of relevant genes that drive pathogenicity and adaptation and at the same time allows for the delineation of phylogenetic relatedness of pathogens that cause specific diseases. In this study, we used mRNA sequencing to acquire information on the expression ofEscherichia colipathogenicity genes during urinary tract infections (UTI) in humans and to assign the UTI-associatedE. coliisolates to different phylogenetic groups. Whereas thein vivogene expression profiles of the majority of genes were conserved among 21E. colistrains in the urine of elderly patients suffering from an acute UTI, the specific gene expression profiles of the flexible genomes was diverse and reflected phylogenetic relationships. Furthermore, genes transcribedin vivorelative to laboratory media included well-described virulence factors, small regulatory RNAs, as well as genes not previously linked to bacterial virulence. Knowledge on relevant transcriptional responses that drive pathogenicity and adaptation of isolates to the human host might lead to the introduction of a virulence typing strategy into clinical microbiology, potentially facilitating management and prevention of the disease.IMPORTANCEUrinary tract infections (UTI) are very common; at least half of all women experience UTI, most of which are caused by pathogenicEscherichia colistrains. In this study, we applied massive parallel cDNA sequencing (RNA-seq) to provide unbiased, deep, and accurate insight into the nature and the dimension of the uropathogenicE. coligene expression profile during an acute UTI within the human host. This work was undertaken to identify key players in physiological adaptation processes and, hence, potential targets for new infection prevention and therapy interventions specifically aimed at sabotaging bacterial adaptation to the human host.

Monitoring expression of genes involved in drug metabolism and toxicology using DNA microarrays

2001 ◽  
Vol 5 (4) ◽  
pp. 161-170 ◽  
Author(s):  
DAVID GERHOLD ◽  
MEIQING LU ◽  
JIAN XU ◽  
CHRISTOPHER AUSTIN ◽  
C. THOMAS CASKEY ◽  
...  
Keyword(s):  
Gene Expression ◽  
Drug Metabolism ◽  
Stress Responses ◽  
Dna Microarrays ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Metabolic Effects ◽  
Microarray Technology ◽  
Drug Candidates ◽  
Expression Of Genes

Oligonucleotide DNA microarrays were investigated for utility in measuring global expression profiles of drug metabolism genes. This study was performed to investigate the feasibility of using microarray technology to minimize the long, expensive process of testing drug candidates for safety in animals. In an evaluation of hybridization specificity, microarray technology from Affymetrix distinguished genes up to a threshold of ∼90% DNA identity. Oligonucleotides representing human cytochrome P-450 gene CYP3A5 showed heterologous hybridization to CYP3A4 and CYP3A7 RNAs. These genes could be clearly distinguished by selecting a subset of oligonucleotides that hybridized selectively to CYP3A5. Further validation of the technology was performed by measuring gene expression profiles in livers of rats treated with vehicle, 3-methylcholanthrene (3MC), phenobarbital, dexamethasone, or clofibrate and by confirming data for six genes using quantitative RT-PCR. Responses of drug metabolism genes, including CYPs, epoxide hydrolases ( EHs), UDP-glucuronosyl transferases ( UGTs), glutathione sulfotransferases ( GSTs), sulfotransferases ( STs), drug transporter genes, and peroxisomal genes, to these well-studied compounds agreed well with, and extended, published observations. Additional gene regulatory responses were noted that characterize metabolic effects or stress responses to these compounds. Thus microarray technology can provide a facile overview of gene expression responses relevant to drug metabolism and toxicology.

scholarly journals Global Gene Expression Responses to Cadmium Toxicity in Escherichia coli

2005 ◽  
Vol 187 (9) ◽  
pp. 3259-3266 ◽  
Author(s):  
Anyou Wang ◽  
David E. Crowley
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Cadmium Toxicity ◽  
Gene Expression Profiles ◽  
Global Gene Expression ◽  
Temporal Gene Expression ◽  
Genes Encoding

ABSTRACT Genome-wide analysis of temporal gene expression profiles in Escherichia coli following exposure to cadmium revealed a shift to anaerobic metabolism and induction of several stress response systems. Disruption in the transcription of genes encoding ribosomal proteins and zinc-binding proteins may partially explain the molecular mechanisms of cadmium toxicity.

scholarly journals Comparative Gene Expression Profiles Following UV Exposure in Wild-Type and SOS-Deficient Escherichia coli

Genetics ◽  
2001 ◽  
Vol 158 (1) ◽  
pp. 41-64 ◽  
Author(s):  
Justin Courcelle ◽  
Arkady Khodursky ◽  
Brian Peter ◽  
Patrick O Brown ◽  
Philip C Hanawalt
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Uv Irradiation ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Uv Exposure ◽  
Dependent Manner ◽  
Wild Type ◽  
Independent Manner ◽  
E Coli

Abstract The SOS response in UV-irradiated Escherichia coli includes the upregulation of several dozen genes that are negatively regulated by the LexA repressor. Using DNA microarrays containing amplified DNA fragments from 95.5% of all open reading frames identified on the E. coli chromosome, we have examined the changes in gene expression following UV exposure in both wild-type cells and lexA1 mutants, which are unable to induce genes under LexA control. We report here the time courses of expression of the genes surrounding the 26 documented lexA-regulated regions on the E. coli chromosome. We observed 17 additional sites that responded in a lexA-dependent manner and a large number of genes that were upregulated in a lexA-independent manner although upregulation in this manner was generally not more than twofold. In addition, several transcripts were either downregulated or degraded following UV irradiation. These newly identified UV-responsive genes are discussed with respect to their possible roles in cellular recovery following exposure to UV irradiation.

scholarly journals Single-Cell transcriptional changes in hypothalamic CRH-expressing neurons after early-life adversity inform enduring alterations in responses to stress

2021 ◽  
Author(s):  
Annabel K Short ◽  
Christina Wilcox ◽  
Yuncai Chen ◽  
Aidan L Pham ◽  
Matthew T Birnie ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Stress Responses ◽  
Life Stress ◽  
Early Life ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Early Life Adversity ◽  
Neuronal Populations ◽  
Transcriptional Changes

AbstractMental and cognitive health, as well as vulnerability to neuropsychiatric disorders, involve the interplay of genes with the environment, particularly during sensitive developmental periods. Early-life stress / adversity (ELA) promotes vulnerabilities to stress-related affective disorders, yet it is unknown how a transient ELA dictates life-long neuroendocrine and behavioral reactions to stress. The population of hypothalamic corticotropin-releasing hormone (CRH)-expressing neurons that regulate stress-responses is a promising candidate to mediate the enduring influences of ELA on stress-related behavioral and hormonal responses via enduring transcriptional and epigenetic mechanisms. Capitalizing on a well-characterized model of ELA, we examined here the ELA-induced changes in gene expression profiles of stress-sensitive CRH-neurons in the hypothalamic paraventricular nucleus (PVN) of male mice. Given the known heterogeneity of these neuronal populations, we employed single-cell RNA sequencing (RNA-seq) approaches. The use of single-cell transcriptomics identified distinct CRH-expressing neuronal populations characterized by both their gene expression repertoire and their neurotransmitter profiles. Expression changes provoked by ELA clustered around genes involved in neuronal differentiation, synapse formation, altered energy metabolism and the cellular responses to stress and injury. Notably, the ELA-induced transcriptional changes took place primarily in subpopulations of glutamatergic CRH cells. Finally, ELA-induced transcriptional reprogramming of hypothalamic CRH-expressing neurons heralded significant, enduring disruptions of both hormonal and behavioral responses to stress throughout life.

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