MNNG treated Excherichia coli reveal new up or down regulated genes belonging to the Ada regulon
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ABSTRACT:
ORGANISM(S): Escherichia coli str. K-12 substr. MG1655
PROVIDER: GSE13830 | GEO | 2009/08/18
SECONDARY ACCESSION(S): PRJNA110505
REPOSITORIES: GEO
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Project description:An oligonucleotide tiling array technology is utilized to measure the entire Escherichia coli transcriptome and its transcriptional changes after induction of the adaptive response by the alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Keywords: Gene expression during the adaptive response in Escherichia coli Escherichia coli K-12 MG1655 single colony in five parallells was grown to mid-log phase and exposed to the ada-response inducer MNNG. Total RNA was extracted from induced and uninduced cells and cDNA was prepared, fragmented and labelled prior to hybridizing to arrays. The Escherichia coli genome was split in two; sequences encoding proteins, tRNAs or rRNAs with a known function on either strand, and sequences without such annotation. A selective tiling approach was used to ensure sufficient coverage of unnanotated genomic regions due to the limited number of array probes.
2010-05-06 | E-GEOD-13830 | biostudies-arrayexpress
Project description:Alkylation damage to DNA occurs when cells encounter alkylating agents in the environment or when active alkylators are generated by nitrosation of amino acids in metabolic pathways. To cope with DNA alkylation damage, cells have evolved genes that encode proteins with alkylation-specific DNA repair activities. It is notable that these repair systems are conserved from bacteria to humans. In Escherichia coli, cells exposed to a low concentration of an alkylating agent, such as N-methyl-N’-nitro-N-nitrosoguanidine (MNNG) or methyl methanesulfonate (MMS), show a remarkable increase in resistance to both the lethal and mutagenic effects of subsequent high-level challenge treatments with the same or other alkylating agents. This increased resistance has been known as “adaptive response” to alkylation damage in DNA. To date, four genes have been identified as components of this response, ada, alkA, alkB and aidB. The ada gene encodes the Ada protein, which has the dual function of a transcriptional regulator for the genes involved in the adaptive response, and a methyltransferase that demethylates two methylated bases (O6meG and O4meT) and methylphosphotriesters produced by methylating agents in the sugar phosphate backbone. The differences between the wild-type and mutant strains were characterized at transcriptome levels. In addition, the global changes in gene expressions in response to alkylating agents (MMS), in E. coli K-12 W3110 and ada mutant strains were also analyzed. The analysis of time- and strain-dependent adaptive responses revealed the regulatory and physiological characteristics of the Ada-dependent adaptive response in E. coli.
2009-08-25 | GSE16565 | GEO
Project description:Alkylation damage to DNA occurs when cells encounter alkylating agents in the environment or when active alkylators are generated by nitrosation of amino acids in metabolic pathways. To cope with DNA alkylation damage, cells have evolved genes that encode proteins with alkylation-specific DNA repair activities. It is notable that these repair systems are conserved from bacteria to humans. In Escherichia coli, cells exposed to a low concentration of an alkylating agent, such as N-methyl-Nâ-nitro-N-nitrosoguanidine (MNNG) or methyl methanesulfonate (MMS), show a remarkable increase in resistance to both the lethal and mutagenic effects of subsequent high-level challenge treatments with the same or other alkylating agents. This increased resistance has been known as âadaptive responseâ to alkylation damage in DNA. To date, four genes have been identified as components of this response, ada, alkA, alkB and aidB. The ada gene encodes the Ada protein, which has the dual function of a transcriptional regulator for the genes involved in the adaptive response, and a methyltransferase that demethylates two methylated bases (O6meG and O4meT) and methylphosphotriesters produced by methylating agents in the sugar phosphate backbone. The differences between the wild-type and mutant strains were characterized at transcriptome levels. In addition, the global changes in gene expressions in response to alkylating agents (MMS), in E. coli K-12 W3110 and ada mutant strains were also analyzed. The analysis of time- and strain-dependent adaptive responses revealed the regulatory and physiological characteristics of the Ada-dependent adaptive response in E. coli. In order to examine the intracellular changes that are induced by the ada gene deletion in the MMS-untreated, normal growth condition, the expression levels of genes of ada mutant cells were compared with those of wild-type cells at the mid-log growth phase (at 0.5 h sampling point). Cells were cultivated at 37oC and 250 rpm in 100 mL of Luria-Bertani (LB) medium (10 g/L tryptone, 5 g/L yeast extract, and 5 g/L NaCl) in 250-mL Erlenmeyer flasks. Transcriptome analysis were also performed for the samples (E. coli wildtype and ada mutant strains) taken at 0.5, 1.5 and 3.9 h following MMS treatment for both MMS-treated and -untreated control cultures, and the expression levels were compared.
2010-09-09 | E-GEOD-16565 | biostudies-arrayexpress
Project description:The alkylating agent N-methyl-N’-nitro-N-nitrosoguanidine (MNNG) induces cellular DNA damages and other comprehensive alterations that lead to chromosomal aberrations, mutations, tumor initiations, and cell death. However, the molecular mechanism of MNNG-induced cellular stress remains unclear.We have genome-wide analyzed early transcriptional responses of human FL amnion epithelial cells after exposure to three relatively low doses of MNNG (0.2, 1.0, and 10.0µM),and differential gene expression profiles were obtained 4 h after exposure using oligonucleotide microarrays followed by validation with quantitative real-time RT-PCR. The results demonstrate that the MNNG-responsive genes are involved in multiple cellular biological processes including transcription regulation, signal transduction, cell cycle regulation, cytoskeleton organization, protein synthesis, immune response, metabolism, etc. The possible roles of these genes and their related pathways in MNNG-induced cellular responses were discussed. This study helps to draw the whole picture how cells respond to environmental chemical exposure via transcriptional regulation. Experiment Overall Design: Human amnion epithelial FL cells were exposed to vehicle control (dimethyl sulfoxide) and increasing doses(0.2, 1.0, and 10.0µM)of N-methyl-N’-nitro-N-nitrosoguanidine(MNNG), respectively. The transcriptomes of the three treatments were compared to that of the control, respectively, to test the hypothesis that a characterized differential expression profile would be generated by exposure to various doses of this genotoxic agent.
2009-01-09 | E-GEOD-8602 | biostudies-arrayexpress
Project description:The alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) is a direct mutagen and carcinogen, causing DNA damage and other comprehensive alterations that lead to chromosomal aberrations, mutations, tumor initiation, and cell death. Our previous study revealed that MNNG at different concentrations could induce extensive changes in gene expression at an early stage of exposure. To further understand the dynamic cellular responses and hazardous effects caused by this environmental carcinogen, we used a whole-genome time-course screening methods to find out the gene expression changes induced by a low concentration of MNNG in human normal amnion epithelial FL cells. The cells were exposed to 1.0 µM MNNG, and differential gene expression profiles at 3, 12, and 24 h after MNNG treatment were obtained by use of Affymetrix HG-U133 Plus 2.0 oligonucleotide microarray technology, followed by quantitative real-time RT-PCR validation. The results showed that the low-dose MNNG exposure triggered extensive but moderate changes in gene expression at these three experiment time points after exposure. The responsive genes encode important proteins, including cell cycle regulators, transcription factors and signal transducers that determine cell cycle progression, cell fate and other activities associate with pro-oncogenic potentials. The differential gene expression profiles at the three time points varied greatly, and generally reflected a cellular responsive process from initiation to progression and to recovery after MNNG exposure. These results will aid our understanding of the complicated mechanisms of MNNG-induced cellular responses. Keywords：N-methyl-N'-nitro-N-nitrosoguanidine; Cellular response; Temporal gene expression change; Oligonucleotide microarray; Quantitative real-time RT-PCR
2013-07-01 | GSE21270 | GEO
Project description:The alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) is a direct mutagen and carcinogen, causing DNA damage and other comprehensive alterations that lead to chromosomal aberrations, mutations, tumor initiation, and cell death. Our previous study revealed that MNNG at different concentrations could induce extensive changes in gene expression at an early stage of exposure. To further understand the dynamic cellular responses and hazardous effects caused by this environmental carcinogen, we used a whole-genome time-course screening methods to find out the gene expression changes induced by a low concentration of MNNG in human normal amnion epithelial FL cells. The cells were exposed to 1.0 M-BM-5M MNNG, and differential gene expression profiles at 3, 12, and 24 h after MNNG treatment were obtained by use of Affymetrix HG-U133 Plus 2.0 oligonucleotide microarray technology, followed by quantitative real-time RT-PCR validation. The results showed that the low-dose MNNG exposure triggered extensive but moderate changes in gene expression at these three experiment time points after exposure. The responsive genes encode important proteins, including cell cycle regulators, transcription factors and signal transducers that determine cell cycle progression, cell fate and other activities associate with pro-oncogenic potentials. The differential gene expression profiles at the three time points varied greatly, and generally reflected a cellular responsive process from initiation to progression and to recovery after MNNG exposure. These results will aid our understanding of the complicated mechanisms of MNNG-induced cellular responses. KeywordsM-oM-<M-^ZN-methyl-N'-nitro-N-nitrosoguanidine; Cellular response; Temporal gene expression change; Oligonucleotide microarray; Quantitative real-time RT-PCR Human amnion epithelial FL cells were exposed to vehicle control (dimethyl sulfoxide) and a low concentration (1.0 M-BM-5M) MNNG for 2 h, respectively. The differential gene expression profiles at 3, 12 and 24 h post MNNG treatment were obtained using Affymetrix HG-U133 Plus 2.0 oligonucleotide microarrays. The transcriptomic changes at different time points post MNNG treatment would provide insight into the dynamic processes of cellular response to this genotoxic agent.
2013-07-01 | E-GEOD-21270 | biostudies-arrayexpress
Project description:The alkylating agent N-methyl-N’-nitro-N-nitrosoguanidine (MNNG) induces cellular DNA damages and other comprehensive alterations that lead to chromosomal aberrations, mutations, tumor initiations, and cell death. However, the molecular mechanism of MNNG-induced cellular stress remains unclear.We have genome-wide analyzed early transcriptional responses of human FL amnion epithelial cells after exposure to three relatively low doses of MNNG (0.2, 1.0, and 10.0µM),and differential gene expression profiles were obtained 4 h after exposure using oligonucleotide microarrays followed by validation with quantitative real-time RT-PCR. The results demonstrate that the MNNG-responsive genes are involved in multiple cellular biological processes including transcription regulation, signal transduction, cell cycle regulation, cytoskeleton organization, protein synthesis, immune response, metabolism, etc. The possible roles of these genes and their related pathways in MNNG-induced cellular responses were discussed. This study helps to draw the whole picture how cells respond to environmental chemical exposure via transcriptional regulation. Keywords: Dose response
2009-01-01 | GSE8602 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE38133: TGF-beta1 effect on human osteosarcoma cell line MNNG/HOS GSE38134: Expression analysis of human osteosarcoma cell line MNNG/HOS sarcospheres, hypoxia-induced sarcospheres and TGF-beta1-induced sarcospheres Refer to individual Series
2012-05-22 | E-GEOD-38135 | biostudies-arrayexpress
Project description:Investigation of whole genome gene expression level changes in human osteosarcoma cell line MNNG/HOS treated by TGF-beta1 for three days (mesophase) and five days (sarcospheres iOSCs), compared to non-treatment cells (residual adherent cells). A three chip study using total RNA cover from three cultures of non-treatment human osteosarcoma cell line MNNG/HOS (residual adherent cells), TGF-beta1 treated three days osteosarcoma cell line MNNG/HOS (mesophase) and TGF-beta1 treated five days osteosarcoma cell line MNNG/HOS ( only collected the suspending sarcospheres iOSCs). Each chip measures the expression level of 45033 genes from osteosarcoma cell line MNNG/HOS.
2012-05-22 | E-GEOD-38133 | biostudies-arrayexpress
Project description:Investigation of whole genome gene expression level changes in human osteosarcoma cell line MNNG/HOS treated by TGF-beta1 for three days (mesophase) and five days (sarcospheres iOSCs), compared to non-treatment cells (residual adherent cells).
2012-05-23 | GSE38133 | GEO