Molecular cloning of AtMMH, an Arabidopsis thaliana ortholog of the Escherichia coli mutM gene, and analysis of functional domains of its product

Ohtsubo, Toshio; Matsuda, Osamu; Iba, Koh; Terashima, Isamu; Sekiguchi, Mutsuo; Nakabeppu, Yusaku

doi:10.1007/s004380050851

Cited by 74 publications

(61 citation statements)

References 54 publications

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“…T transversions. These results were predicted by earlier reports of their ability in vitro to cleave DNA containing 8-oxo-G (OGG: [8,11]; FPG: [2,12]. 8-Oxo-G base-pairs equally well with A and C. To the degree that the A is not removed from an 8-oxo-G:A base-pair by the MutY gene product, adenine-DNA glycosylase, the next round of replication will yield a stable T:A base-pair (and an active b-galactosidase if this base-pair is in the appropriate position in the lacZ gene).…”

Section: Discussionsupporting

confidence: 85%

“…In contrast, the Arabidopsis ogg gene produces only one type of mRNA by splicing [8]. To our knowledge, there is as yet no evidence for the targeting of plant OGG or FPG proteins to various organelles, but Arabidopsis OGG is predicted through sequence analysis to be localized in mitochondria or plastids [18] and Arabidopsis FPG-1 has a predicted nuclear localization signal [12]. These predictions are opposite to what might be expected from evolutionary considerations.…”

Section: Plasmidmentioning

confidence: 99%

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Antimutagenic specificities of two plant glycosylases, oxoguanine glycosylase and formamidopyrimidine glycosylase, assayed in vivo

Murphy¹,

Guo²

2010

Biochemical and Biophysical Research Communications

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a b s t r a c tThe base-excision repair process protects genomes by removing and replacing altered bases in DNA. Two analogous glycosylases, oxoguanine glycosylase (OGG) and formamidopyrimidine glycosylase (FPG), can start the process by removing oxidized guanine, the most common modification that leads to misreading of DNA. Plants possess genes for both types of glycosylases. We have tested the hypothesis that the two enzymes in plants have diverged in their specificities by inserting the genes for each enzyme from Arabidopsis thaliana L. into Escherichia coli strains designed to indicate the frequencies of the six possible single-base changes. Both enzymes retain the ability to reduce the rate of GC ? TA transversion mutations. Both enzymes also reduce the frequency of two other base-change mutations, GC ? AT and AT ? TA. We do not find a divergence in the repair capabilities of the two enzymes, as measured in E. coli, although surprisingly FPG appears to increase the rate of mutations in one particular strain.Ó 2010 Elsevier Inc. All rights reserved. IntroductionModification of bases in DNA is a common occurrence in cells and one with potentially serious mutagenic consequences. One of the most common modifications is oxidation of guanine. 7,8-Dihydro-8-oxoguanine (8-oxo-G) base-pairs equally well with cytosine and adenine, leading to GC ? TA transversions. Virtually all organisms have a glycosylase that recognizes and removes 8-oxo-G from DNA, leading to its replacement by unmodified G through the subsequent reactions of the base-excision repair pathway. In archaea, fungi, and animals, the effective glycosylase is oxoguanine glycosylase (OGG); in bacteria, it is formamidopyrimidine glycosylase (FPG). Plants, uniquely, have genes for both enzymes. Furthermore, plant cells have variants of the mRNA for FPG produced by alternative splicing [1,2].The reason for the retention in plants of the genes for both OGG and FPG and the diversity of FPG variants is not known. It is reasonable to speculate that the presence of photosynthetic metabolism, with the resulting high concentration of diatomic oxygen and oxygen radicals, creates a particular need for protection of the genome against oxidative damage. However, knock-out mutants that lack genes for either OGG or FPG, or both, show no obvious phenotype over several generations [3], so the adaptive value of the genes must be subtle or important under unusual circumstances that have not yet been identified. It is also possible that the presence of two analogous genes has allowed one or both to alter the specificity of their protein products, allowing them to recognize additional base modifications. It is known that the glycosylases can have multiple specificities. Bacterial FPG was first shown to act on ring-opened purines [4].To test the specificities of the plant enzymes, we have inserted cDNAs for OGG and FPG from Arabidopsis thaliana into Escherichia coli strains, devised by Cupples and Miller [5] to test for single-base substitution mutations, in which the endogeno...

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Section: Discussionsupporting

confidence: 85%

Section: Plasmidmentioning

confidence: 99%

Antimutagenic specificities of two plant glycosylases, oxoguanine glycosylase and formamidopyrimidine glycosylase, assayed in vivo

Murphy¹,

Guo²

2010

Biochemical and Biophysical Research Communications

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“…In higher organisms, similar enzyme activities have been detected, and may account for the rapid elimination of 8-oxoguanine from chromosomal DNA. These include two types of MutM-related proteins, OGG1 and AtMMH, which carry 8-oxoguanine-DNA glycosylase activity (van der Kemp et al, 1996;Nash et al, 1996;Ohtsubo et al, 1998;Boiteux and Radicella, 1999), and MYH protein that excises adenine paired with 8-oxoguanine in DNA (Yeh et al, 1991;Slupska et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Oxidative nucleotide damage: consequences and prevention

Sekiguchi¹,

2002

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is produced in DNA, as well as in nucleotide pools of cells, by reactive oxygen species normally formed during cellular metabolic processes. 8-Oxoguanine nucleotide can pair with cytosine and adenine nucleotides with an almost equal efficiency, then transversion mutation ensues. MutT protein of Escherichia coli and related mammalian protein MTH1 specifically degrade 8-oxo-dGTP to 8-oxo-dGMP, thereby preventing misincorporation of 8-oxoguanine into DNA. The bacterial and mammalian enzymes are close in their size and share a highly conserved region consisting of 23 residues with 14 identical amino acids. Following saturation mutagenesis of this region, most of these residues proved to be essential to exert 8-oxo-dGTPase activity. Gene targeting was done to establish MTH1-deficient cell lines and mice for study. When examined 18 months after birth, a greater number of tumors were formed in the lungs, livers, and stomachs of MTH1 7/7 mice, as compared with findings in wild-type mice. These proteins protect genetic information from untoward effects of threats of endogenous oxygen.

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“…In eukaryotes, the only mutM homologous gene known has been found in A. thaliana (AtMMH). This gene encodes two types of mRNA (AtMMH1 and AtMMH2), formed by alternative splicing of exon 8 (Ohtsubo et al, 1998). In the SUCEST database we found four clusters presenting high similarity with MutM proteins (Table I).…”

Section: Discussionmentioning

confidence: 95%

“…The A. thaliana thi1 gene is homologous to the yeast thi4 gene and seems to be involved in thiamine biosynthesis and mitochondrial DNA damage tolerance (Machado et al, 1996;Machado et al, 1997). The AtMMH gene is homologous to the E. coli mutM gene, which encodes for a glycosylase that recognizes some types of oxidative deoxyguanosine dam-age (Ohtsubo et al, 1998). The A. thaliana UVR3 gene shows homology with 6-4 photolyase genes from Drosophila melanogaster and Xenopus laevis, which act in the repair of 6-4 photoproducts (Nakajima et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Base excision repair in sugarcane

et al. 2001

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DNA damage can be induced by a large number of physical and chemical agents from the environment as well as compounds produced by cellular metabolism. This type of damage can interfere with cellular processes such as replication and transcription, resulting in cell death and/or mutations. The low frequency of mutagenesis in cells is due to the presence of enzymatic pathways which repair damaged DNA. Several DNA repair genes (mainly from bacteria, yeasts and mammals) have been cloned and their products characterized. The high conservation, especially in eukaryotes, of the majority of genes related to DNA repair argues for their importance in the maintenance of life on earth. In plants, our understanding of DNA repair pathways is still very poor, the first plant repair genes having only been cloned in 1997 and the mechanisms of their products have not yet been characterized. The objective of our data mining work was to identify genes related to the base excision repair (BER) pathway, which are present in the database of the Sugarcane Expressed Sequence Tag (SUCEST) Project. This search was performed by tblastn program. We identified sugarcane clusters homologous to the majority of BER proteins used in the analysis and a high degree of conservation was observed. The best results were obtained with BER proteins from Arabidopsis thaliana. For some sugarcane BER genes, the presence of more than one form of mRNA is possible, as shown by the occurrence of more than one homologous EST cluster.

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Molecular cloning of AtMMH, an Arabidopsis thaliana ortholog of the Escherichia coli mutM gene, and analysis of functional domains of its product

Cited by 74 publications

References 54 publications

Antimutagenic specificities of two plant glycosylases, oxoguanine glycosylase and formamidopyrimidine glycosylase, assayed in vivo

Antimutagenic specificities of two plant glycosylases, oxoguanine glycosylase and formamidopyrimidine glycosylase, assayed in vivo

Oxidative nucleotide damage: consequences and prevention

Base excision repair in sugarcane

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