title: Tiling array study of MNNG treated Escherichia coli reveals a widespread transcriptional response.
abstract: The alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) is known to trigger the adaptive response by inducing the ada-regulon - consisting of three DNA repair enzymes Ada, AlkB, AlkA and the enigmatic AidB. We have applied custom designed tiling arrays to study transcriptional changes in Escherichia coli following a MNNG challenge. Along with the expected upregulation of the adaptive response genes (ada, alkA and alkB), we identified a number of differentially expressed transcripts, both novel and annotated. This indicates a wider regulatory response than previously documented. There were 250 differentially-expressed and 2275 similarly-expressed unannotated transcripts. We found novel upregulation of several stress-induced transcripts, including the SOS inducible genes recN and tisAB, indicating a novel role for these genes in alkylation repair. Furthermore, the ada-regulon A and B boxes were found to be insufficient to explain the regulation of the adaptive response genes after MNNG exposure, suggesting that additional regulatory elements must be involved.
authors.affiliation: 1] Centre for Molecular Biology and Neuroscience (CMBN) and Department of Microbiology, Oslo University Hospital, Rikshospitalet, PO Box 4950 Nydalen, NO-0424 Oslo, Norway [2] Department of Microbiology, University of Oslo, PO Box 4950 Nydalen, NO-0424 Oslo, Norway [3].
authors.forename: James A
authors.initials: JA
authors.lastname: Booth
authors.forename: Gard O S
authors.initials: GO
authors.lastname: Thomassen
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Rowe
authors.forename: Ragnhild
authors.initials: R
authors.lastname: Weel-Sneve
authors.forename: Karin
authors.initials: K
authors.lastname: Lagesen
authors.forename: Knut I
authors.initials: KI
authors.lastname: Kristiansen
authors.forename: Magnar
authors.initials: M
authors.lastname: Bjørås
authors.forename: Torbjørn
authors.initials: T
authors.lastname: Rognes
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Lindvall
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology*; D009154:Mutation; D009876:Operon; D011401:Promoter Regions, Genetic; D022661:RNA, Untranslated / Q000235:genetics; D015203:Reproducibility of Results; D014158:Transcription, Genetic; D059467:Transcriptome; D020506:Untranslated Regions
chemical_list: D022661:RNA, Untranslated; D020506:Untranslated Regions; D008769:Methylnitronitrosoguanidine