title: Extreme dNTP pool changes and hypermutability in dcd ndk strains.
abstract: Cells lacking deoxycytidine deaminase (DCD) have been shown to have imbalances in the normal dNTP pools that lead to multiple phenotypes, including increased mutagenesis, increased sensitivity to oxidizing agents, and to a number of antibiotics. In particular, there is an increased dCTP pool, often accompanied by a decreased dTTP pool. In the work presented here, we show that double mutants of Escherichia coli lacking both DCD and NDK (nucleoside diphosphate kinase) have even more extreme imbalances of dNTPs than mutants lacking only one or the other of these enzymes. In particular, the dCTP pool rises to very high levels, exceeding even the cellular ATP level by several-fold. This increased level of dCTP, coupled with more modest changes in other dNTPs, results in exceptionally high mutation levels. The high mutation levels are attenuated by the addition of thymidine. The results corroborate the critical importance of controlling DNA precursor levels for promoting genome stability. We also show that the addition of certain exogenous nucleosides can influence replication errors in DCD-proficient strains that are deficient in mismatch repair.
authors.affiliation: Department of Microbiology, Immunology, and Molecular Genetics, The Molecular Biology Institute, University of California and the David Geffen School of Medicine, Los Angeles, CA 90095, United States.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Tse
authors.affiliation: Department of Microbiology, Immunology, and Molecular Genetics, The Molecular Biology Institute, University of California and the David Geffen School of Medicine, Los Angeles, CA 90095, United States.
authors.forename: Tina Manzhu
authors.initials: TM
authors.lastname: Kang
authors.affiliation: Department of Microbiology, Immunology, and Molecular Genetics, The Molecular Biology Institute, University of California and the David Geffen School of Medicine, Los Angeles, CA 90095, United States.
authors.forename: Jessica
authors.initials: J
authors.lastname: Yuan
authors.affiliation: Department of Microbiology, Immunology, and Molecular Genetics, The Molecular Biology Institute, University of California and the David Geffen School of Medicine, Los Angeles, CA 90095, United States.
authors.forename: Danielle
authors.initials: D
authors.lastname: Mihora
authors.affiliation: Department of Microbiology, Immunology, and Molecular Genetics, The Molecular Biology Institute, University of California and the David Geffen School of Medicine, Los Angeles, CA 90095, United States.
authors.forename: Elinne
authors.initials: E
authors.lastname: Becket
authors.affiliation: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, United States.
authors.forename: Katarzyna H
authors.initials: KH
authors.lastname: Maslowska
authors.affiliation: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, United States.
authors.forename: Roel M
authors.initials: RM
authors.lastname: Schaaper
authors.affiliation: Department of Microbiology, Immunology, and Molecular Genetics, The Molecular Biology Institute, University of California and the David Geffen School of Medicine, Los Angeles, CA 90095, United States. Electronic address: jhmiller@microbio.ucla.edu.
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Miller
mesh_terms: D003564:Cytidine Deaminase / Q000235:genetics* / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases; D003854:Deoxyribonucleotides / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D059645:Mutation Rate; D009701:Nucleoside-Diphosphate Kinase / Q000235:genetics* / Q000378:metabolism; D013936:Thymidine / Q000494:pharmacology
chemical_list: D003854:Deoxyribonucleotides; D029968:Escherichia coli Proteins; C540081:rpoB protein, E coli; D009701:Nucleoside-Diphosphate Kinase; D012321:DNA-Directed RNA Polymerases; D003564:Cytidine Deaminase; C011530:deoxycytidine deaminase; D013936:Thymidine
keywords: Hypermutability; dNTP pools; dcd ndk mutant