Transcriptome analysis of Escherichia coli K-12 and ada mutant
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ABSTRACT:
ORGANISM(S): Escherichia coli K-12 Escherichia coli
PROVIDER: GSE16565 | GEO | 2009/08/25
SECONDARY ACCESSION(S): PRJNA116205
REPOSITORIES: GEO
Similar Datasets
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:Despite the high toxicity, alkylating agents are still at the forefront of several clinical protocols used to treat cancers. In this study, we investigated the mechanisms underlying alkylation damage responses, aiming to identify novel strategies to augment alkylating therapy efficacy. In this pursuit, we compared gene expression profiles of evolutionary distant cell types (D. melanogaster Kc167 cells, mouse embryonic fibroblasts and human cancer cells) in response to the alkylating agent methyl-methanesulfonate (MMS). We found that many responses to alkylation damage are conserved across species independent on their tumor/normal phenotypes. Key amongst these observations was the protective role of NRF2-induced GSH production primarily regulating GSH pools essential for MMS detoxification but also controlling activation of unfolded protein response (UPR) needed for mounting survival responses across species. An interesting finding emerged from a non-conserved mammalian-specific induction of mitogen activated protein kinase (MAPK)-dependent inflammatory responses following alkylation, which was not directly related to cell survival but stimulated the production of a pro-inflammatory, invasive and angiogenic secretome in cancer cells. Appropriate blocking of this inflammatory component blocked the invasive phenotype and angiogenesis in vitro and facilitated a controlled tumor killing by alkylation in vivo through inhibition of alkylation-induced angiogenic response, and induction of tumor healing.
2020-05-06 | GSE57161 | GEO
Project description:Despite the high toxicity, alkylating agents are still at the forefront of several clinical protocols used to treat cancers. In this study, we investigated the mechanisms underlying alkylation damage responses, aiming to identify novel strategies to augment alkylating therapy efficacy. In this pursuit, we compared gene expression profiles of evolutionary distant cell types (D. melanogaster Kc167 cells, mouse embryonic fibroblasts and human cancer cells) in response to the alkylating agent methyl-methanesulfonate (MMS). We found that many responses to alkylation damage are conserved across species independent on their tumor/normal phenotypes. Key amongst these observations was the protective role of NRF2-induced GSH production primarily regulating GSH pools essential for MMS detoxification but also controlling activation of unfolded protein response (UPR) needed for mounting survival responses across species. An interesting finding emerged from a non-conserved mammalian-specific induction of mitogen activated protein kinase (MAPK)-dependent inflammatory responses following alkylation, which was not directly related to cell survival but stimulated the production of a pro-inflammatory, invasive and angiogenic secretome in cancer cells. Appropriate blocking of this inflammatory component blocked the invasive phenotype and angiogenesis in vitro and facilitated a controlled tumor killing by alkylation in vivo through inhibition of alkylation-induced angiogenic response, and induction of tumor healing.
2017-02-14 | GSE57789 | GEO
Project description:Despite the high toxicity, alkylating agents are still at the forefront of several clinical protocols used to treat cancers. In this study, we investigated the mechanisms underlying alkylation damage responses, aiming to identify novel strategies to augment alkylating therapy efficacy. In this pursuit, we compared gene expression profiles of evolutionary distant cell types (D. melanogaster Kc167 cells, mouse embryonic fibroblasts and human cancer cells) in response to the alkylating agent methyl-methanesulfonate (MMS). We found that many responses to alkylation damage are conserved across species independent on their tumor/normal phenotypes. Key amongst these observations was the protective role of NRF2-induced GSH production primarily regulating GSH pools essential for MMS detoxification but also controlling activation of unfolded protein response (UPR) needed for mounting survival responses across species. An interesting finding emerged from a non-conserved mammalian-specific induction of mitogen activated protein kinase (MAPK)-dependent inflammatory responses following alkylation, which was not directly related to cell survival but stimulated the production of a pro-inflammatory, invasive and angiogenic secretome in cancer cells. Appropriate blocking of this inflammatory component blocked the invasive phenotype and angiogenesis in vitro and facilitated a controlled tumor killing by alkylation in vivo through inhibition of alkylation-induced angiogenic response, and induction of tumor healing.
2017-02-14 | GSE57788 | GEO
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:Understanding the mechanisms by which cells respond to chemotherapeutics is key to identifying means to improve therapy effiicacy while reducing systemic toxicity of these widely used classes of drugs. While determining the role of NRF2-GSH and ER stress in cells exposed to alkylating compounds such as methyl-methanesulfonate (MMS), we asked if these pathways could also be a general cell damage response relevant to other clinically used chemotherapeutics or if it is an alkylation specific response. With this intent, we performed RNA sequencing of MDA-MB231 breast cancer and U2OS osteosarcoma cells lines treated for 8 hours with a topoisomerase II inhibitor etoposide (20 µM), the antimitotic beta-tubulin-interacting drug paclitaxel (0.2 µM), doxorubicin (1 µM) and compared to MMS (40 µg/mL) treated cells. Doses represent IC50 level after 72 hours exposure. We observed that even though non-alkylating drugs, especially etoposide, caused an increase in the mRNA expression of some NRF2 and ER stress signaling markers, the number and magnitude of upregulation of genes markers in either pathway was more pronounced in alkylation treatments compared to other drugs. This indicates that alterations in NRF2 and ER stress pathways could be more likely associated with differential sensitivity to alkylating chemotherapies.
2017-02-13 | GSE84863 | GEO
Project description:Certain environmental toxins are nucleic acid damaging agents, as are many chemotherapeutics used for cancer therapy. These agents induce various adducts in DNA as well as RNA. Indeed, most of the nucleic acid adducts (>90%) formed due to these chemicals, such as alkylating agents, occur in RNA. However, compared to the well-studied mechanisms for DNA alkylation repair, the biological consequences of RNA damage are largely unexplored. Here, we demonstrate that RNA damage can directly result in loss of genome integrity. Specifically, we show that a human YTH domain-containing protein, YTHDC1, regulates alkylation damage responses in association with the THO complex (THOC). In addition to its established binding to N6-methyladenosine (m6A)-containing RNAs, YTHDC1 binds to N1-methyladenosine (m1A)-containing RNAs upon alkylation. In the absence of YTHDC1, alkylation damage results in increased alkylation damage sensitivity and DNA breaks. Such phenotypes are fully attributable to RNA damage, since an RNA-specific dealkylase can rescue these phenotypes. These RNA damage-induced DNA breaks (RDIBs) depend on R-loop formation and the processing is mediated by the factors involved in the transcription-coupled nucleotide excision repair. Strikingly, in the absence of YTHDC1 or THOC, an RNA m1A methyltransferase targeted to the nucleus is sufficient to induce DNA breaks. Our results uncover a unique role of YTHDC1-THOC in base damage responses by preventing RDIBs, providing definitive evidence for how damaged RNAs can impact genomic integrity.
2024-12-03 | GSE283317 | GEO
Project description:Humans are exposed to a wide range of exogenous and endogenous alkylating agents, including agents frequently used as cytostatic drugs in cancer treatment (Drablos, Feyzi et al. 2004). Alkylating agents are mutagenic and cytotoxic and the major body of research has focused on their effects upon DNA. Less is known about the cellular consequences of alkylation to RNA, proteins and lipids, although such damage is likely quantitatively dominating due to the mere abundance of these macromolecules. DNA and RNA can be alkylated by SN1 and SN2 alkylating agents and alkylation occurs at nucleophilic O and N-atoms in the nucleosides as well as at O atoms in the phosphodiester bonds (Shooter, Howse et al. 1974, Sedgwick 2004). While alkylation at the O atoms in the nucleobases (O6G, O4T and O2C) are not affected by their hydrogen bonding, N1A and N3C contain an electron pair involved in hydrogen bonding. Alkylation at these nitrogens are thus more frequent in RNA and single-stranded DNA than in double stranded DNA (Bodell and Singer 1979). To cope with genomic damage inflicted by alkylating agents, a set of complex signal transduction pathways and DNA repair enzymes, collectively called the DNA damage response (DDR) is essential. The DDR senses the DNA damage and starts a highly choreographed response in order to resolve DNA damage or -replication issues (Ciccia and Elledge 2010). Specific repair mechanisms also exist to repair alkylated RNA (Aas, Otterlei et al. 2003, Wurtmann and Wolin 2009), although the biological significance of such repair yet remains elusive. Nevertheless, alkylation damage has been shown to alter the base-pairing properties of RNA bases and can interfere with tRNA-rRNA (Yoshizawa, Fourmy et al. 1999) as well as mRNA-tRNA (Ougland, Zhang et al. 2004){Hudson, 2015 #259}. Likely, other RNA functions that relies on base pairing might also be affected by alkylation damage, e.g. the correct folding of tRNAs and the function of miRNAs. Alkylation of mRNA may also affect translation indirectly by affecting binding affinities to RNA binding proteins (RBPs), as recently demonstrated for 6-meA. This enzymatically induced modification promotes binding of the 6-maA reader proteins YTHDF1 and 2 . While YTHDF2 reduces the stability of 6-maA modified transcripts (Wang, Lu et al. 2014), YTHDF1 actively promotes protein synthesis by interacting with the translation machinery (Wang, Zhao et al. 2015). To what degree alkylation damage to mRNA may promote similar effects by modulating translation remains, however, to be investigated. Interestingly, several studies have identified RBPs as important players in the DDR (Beli, Lukashchuk et al. 2012, Jungmichel, Rosenthal et al. 2013). Here, RBPs appear to have three major roles: 1) regulate gene expression at both the transcriptional- and post-transcriptional level (Keene and Tenenbaum 2002, Glisovic, Bachorik et al. 2008, Rinn and Chang 2012), 2) prevent formation of R-loops (Skourti-Stathaki and Proudfoot 2014), and 3) participate directly in DNA repair (Montecucco and Biamonti 2013, Dutertre, Lambert et al. 2014, Naro, Bielli et al. 2015). Two large-scale mass spectrometry (MS) based studies of RBPs in human cancer cell lines together identified more than 1100 RBPs (Baltz, Munschauer et al. 2012, Castello, Fischer et al. 2012) and more recently the “RBPomes” of mouse embryonic stem cells (Kwon, Yi et al. 2013) and yeast (Mitchell, Jain et al. 2013) have been published. However, functional studies describing how these complex protein networks are affected during genotoxic cell stress are still largely missing. One previous study has monitored changes in the RBPome of mouse embryonic fibroblasts subsequent to treatment with the topoisomerase inhibitor etoposide {Boucas, 2015 #112}. To our knowledge, however, no such studies have attempted to monitor altered global protein:RNA binding subsequent to treatment with alkylating agents. This could be particularly interesting since base methylation constitutes an important functional modification of RNA. In the present study we aimed at investigating this in more detail by SILAC-based quantitation of proteins differentially binding to poly(A)-RNA in HeLa cells at different time points after treatment with the alkylating agent methyl methanesulfonate.
2021-08-30 | PXD003549 | Pride
Project description:DNA base damage arises frequently in all living cells and is an important contributor to mutations and genome instability. The main repair pathway for base damage is base excision repair (BER). How the formation and repair of base lesions are modulated by DNA-binding proteins is poorly understood. Here we used a high-throughput damage mapping method, N-methylpurine-sequencing (NMP-seq), to characterize alkylation damage distribution and BER at yeast transcription factor (TF) binding sites upon the treatment with alkylating agent methyl methanesulfonate (MMS). We found that formation of alkylation damage was mainly suppressed at the binding sites of yeat TFs Abf1 and Reb1, but individual hotspots with elevated damage formation were also observed. Furthermore, our data indicates that repair of alkyhlation damage by BER was significantly inhibited both within the TF core motif and its adajcent DNA. The modulation of damage formation and BER was caused by the TF binding, because lesion formation and repair can be restored by depletion of Abf1 or Reb1 from the nucleus. Finally, we show that repair of UV damage by nucleotide excision repair (NER) was also inhibited at the binding sites of Abf1 and Reb1. A comparision between alkylyation and UV damage repair reveals that NER was inhibited in a broader DNA region relative to BER. Thus, our analyses indicate that TF binding significantly modulates alkylation damage formation and inhibits repair by the BER pathway. The interplay between base damage formation and BER may play an important role in affecting mutation frequency in gene regulatory regions.
2021-12-31 | GSE183622 | GEO
Project description:DNA base damage is an important contributor to genome instability, but how the formation and repair of these lesions is affected by the genomic landscape is unknown. Here we describe genome-wide maps of DNA base damage, repair, and mutagenesis at single nucleotide resolution in yeast treated with the alkylating agent methyl methanesulfonate (MMS). Analysis of these maps revealed that base excision repair (BER) of alkylation damage is significantly modulated by chromatin, with faster repair in nucleosome free regions, and slower repair and higher mutation density within strongly positioned nucleosomes. Both the translational and rotational settings of lesions within nucleosomes significantly influence BER efficiency; moreover, this effect is asymmetric relative to the nucleosome dyad and is regulated by histone modifications. Our data also indicate that MMS-induced A mutations are significantly enriched on the non-transcribed strand (NTS) of yeast genes, particularly in BER-deficient strains, due to higher damage formation on the NTS and transcription-coupled repair of the transcribed strand (TS). These findings reveal the influence of chromatin on repair and mutagenesis of base lesions on a genome-wide scale, and suggest a novel mechanism for transcription-associated mutation asymmetry, which is frequently observed in human cancers.
2017-08-10 | GSE98031 | GEO