| Escherichia coli DNA glycosylase Mug: a growth-regulated enzyme required for mutation avoidance in stationary-phase cells. | |
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MedLine Citation:
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PMID: 11555290 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The Escherichia coli DNA glycosylase Mug excises 3,N(4)-ethenocytosines (epsilon C) and uracils from DNA, but its biological function is obscure. This is because epsilon C is not found in E. coli DNA, and uracil-DNA glycosylase (Ung), a distinct enzyme, is much more efficient at removing uracils from DNA than Mug. We find that Mug is overexpressed as cells enter stationary phase, and it is maintained at a fairly high level in resting cells. This is true of cells grown in rich or minimal media, and the principal regulation of mug is at the level of mRNA. Although the expression of mug is strongly dependent on the stationary-phase sigma factor, sigma(S), when cells are grown in minimal media, it shows only a modest dependence on sigma(S) when cells are grown in rich media. When mug cells are maintained in stationary phase for several days, they acquire many more mutations than their mug(+) counterparts. This is true in ung as well as ung(+) cells, and a majority of new mutations may not be C to T. Our results show that the biological role of Mug parallels its expression in cells. It is expressed poorly in exponentially growing cells and has no apparent role in mutation avoidance in these cells. In contrast, Mug is fairly abundant in stationary-phase cells and has an important anti-mutator role at this stage of cell growth. Thus, Mug joins a very small coterie of DNA repair enzymes whose principal function is to avoid mutations in stationary-phase cells. |
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Authors:
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S K Mokkapati; A R Fernández de Henestrosa; A S Bhagwat |
Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Molecular microbiology Volume: 41 ISSN: 0950-382X ISO Abbreviation: Mol. Microbiol. Publication Date: 2001 Sep |
Date Detail:
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Created Date: 2001-09-13 Completed Date: 2002-02-11 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 8712028 Medline TA: Mol Microbiol Country: England |
Other Details:
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Languages: eng Pagination: 1101-11 Citation Subset: IM |
Affiliation:
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Department of Chemistry, 463 Chemistry Building, Wayne State University, Detroit, MI 48202, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Bacterial Proteins
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genetics,
metabolism Culture Media DNA Glycosylases* DNA Repair Escherichia coli / enzymology*, growth & development* Gene Expression Regulation, Bacterial* Mutation* N-Glycosyl Hydrolases / genetics, metabolism* RNA, Messenger / genetics, metabolism Sigma Factor / genetics, metabolism Thymine DNA Glycosylase* Uracil-DNA Glycosidase |
| Grant Support | |
ID/Acronym/Agency:
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GM53273/GM/NIGMS NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Bacterial Proteins; 0/Culture Media; 0/RNA, Messenger; 0/Sigma Factor; 0/sigma factor KatF protein, Bacteria; EC 3.2.2.-/DNA Glycosylases; EC 3.2.2.-/N-Glycosyl Hydrolases; EC 3.2.2.-/Thymine DNA Glycosylase; EC 3.2.2.-/Uracil-DNA Glycosidase; EC 3.2.2.-/mismatch-specific thymine uracil-DNA glycosylase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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