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dc.contributor.authorElder, Rhoderick H
dc.contributor.authorJansen, J G
dc.contributor.authorWeeks, Robert J
dc.contributor.authorWillington, Mark
dc.contributor.authorDeans, Bryan
dc.contributor.authorWatson, Amanda J
dc.contributor.authorMynett, Kurt J
dc.contributor.authorBailey, John
dc.contributor.authorCooper, Donald P
dc.contributor.authorRafferty, Joseph A
dc.contributor.authorHeeran, Mel C
dc.contributor.authorWijnhoven, S W
dc.contributor.authorVan Zeeland, A A
dc.contributor.authorMargison, Geoffrey P
dc.date.accessioned2010-02-25T10:52:41Z
dc.date.available2010-02-25T10:52:41Z
dc.date.issued1998-10
dc.identifier.citationAlkylpurine-DNA-N-glycosylase knockout mice show increased susceptibility to induction of mutations by methyl methanesulfonate. 1998, 18 (10):5828-37 Mol. Cell. Biol.en
dc.identifier.issn0270-7306
dc.identifier.pmid9742100
dc.identifier.urihttp://hdl.handle.net/10541/93018
dc.description.abstractAlkylpurine-DNA-N-glycosylase (APNG) null mice have been generated by homologous recombination in embryonic stem cells. The null status of the animals was confirmed at the mRNA level by reverse transcription-PCR and by the inability of cell extracts of tissues from the knockout (ko) animals to release 3-methyladenine (3-meA) or 7-methylguanine (7-meG) from 3H-methylated calf thymus DNA in vitro. Following treatment with DNA-methylating agents, increased persistence of 7-meG was found in liver sections of APNG ko mice in comparison with wild-type (wt) mice, demonstrating an in vivo phenotype for the APNG null animals. Unlike other null mutants of the base excision repair pathway, the APNG ko mice exhibit a very mild phenotype, show no outward abnormalities, are fertile, and have an apparently normal life span. Neither a difference in the number of leukocytes in peripheral blood nor a difference in the number of bone marrow polychromatic erythrocytes was found when ko and wt mice were exposed to methylating or chloroethylating agents. These agents also showed similar growth-inhibitory effects in primary embryonic fibroblasts isolated from ko and wt mice. However, treatment with methyl methanesulfonate resulted in three- to fourfold more hprt mutations in splenic T lymphocytes from APNG ko mice than in those from wt mice. These mutations were predominantly single-base-pair changes; in the ko mice, they consisted primarily of AT-->TA and GC-->TA transversions, which most likely are caused by 3-meA and 3- or 7-meG, respectively. These results clearly show an important role for APNG in attenuating the mutagenic effects of N-alkylpurines in vivo.
dc.language.isoenen
dc.subject.meshAnimals
dc.subject.meshBone Marrow Cells
dc.subject.meshCells, Cultured
dc.subject.meshDNA Glycosylases
dc.subject.meshDacarbazine
dc.subject.meshErythrocytes
dc.subject.meshEthylnitrosourea
dc.subject.meshFemale
dc.subject.meshFibroblasts
dc.subject.meshGuanine
dc.subject.meshHypoxanthine Phosphoribosyltransferase
dc.subject.meshLeukocyte Count
dc.subject.meshLiver
dc.subject.meshMale
dc.subject.meshMethyl Methanesulfonate
dc.subject.meshMice
dc.subject.meshMice, Inbred C57BL
dc.subject.meshMice, Inbred DBA
dc.subject.meshMice, Knockout
dc.subject.meshMutagens
dc.subject.meshMutation
dc.subject.meshN-Glycosyl Hydrolases
dc.titleAlkylpurine-DNA-N-glycosylase knockout mice show increased susceptibility to induction of mutations by methyl methanesulfonate.en
dc.typeArticleen
dc.contributor.departmentCRC Section of Genome Damage and Repair, Paterson Institute for Cancer Research, Christie Hospital (NHS) Trust, Manchester M20 4BX, United Kingdom. RElder@picr.man.ac.uken
dc.identifier.journalMolecular and Cellular Biologyen
html.description.abstractAlkylpurine-DNA-N-glycosylase (APNG) null mice have been generated by homologous recombination in embryonic stem cells. The null status of the animals was confirmed at the mRNA level by reverse transcription-PCR and by the inability of cell extracts of tissues from the knockout (ko) animals to release 3-methyladenine (3-meA) or 7-methylguanine (7-meG) from 3H-methylated calf thymus DNA in vitro. Following treatment with DNA-methylating agents, increased persistence of 7-meG was found in liver sections of APNG ko mice in comparison with wild-type (wt) mice, demonstrating an in vivo phenotype for the APNG null animals. Unlike other null mutants of the base excision repair pathway, the APNG ko mice exhibit a very mild phenotype, show no outward abnormalities, are fertile, and have an apparently normal life span. Neither a difference in the number of leukocytes in peripheral blood nor a difference in the number of bone marrow polychromatic erythrocytes was found when ko and wt mice were exposed to methylating or chloroethylating agents. These agents also showed similar growth-inhibitory effects in primary embryonic fibroblasts isolated from ko and wt mice. However, treatment with methyl methanesulfonate resulted in three- to fourfold more hprt mutations in splenic T lymphocytes from APNG ko mice than in those from wt mice. These mutations were predominantly single-base-pair changes; in the ko mice, they consisted primarily of AT-->TA and GC-->TA transversions, which most likely are caused by 3-meA and 3- or 7-meG, respectively. These results clearly show an important role for APNG in attenuating the mutagenic effects of N-alkylpurines in vivo.


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