Abstract Apurinic/apyrimidinic (AP) endonucleases are key enzymes responsible for the repair of base-less nucleotides generated by spontaneous hydrolysis or as DNA intermediates. APE1, major human AP endonuclease, is a druggable target in cancer and its biological function has been extensively studied. However, molecular features substrate specificity poorly understood. We show here that, contrast to Arabidopsis ortholog ARP (apurinic endonuclease-redox protein) exhibits orphan...

Oxidation of guanine in DNA generates 7,8-dihydro-8-oxoguanine (8-oxoG), an ubiquitous lesion with mutagenic properties. 8-oxoG is primarily removed by glycosylases distributed two families, typified bacterial Fpg proteins and eukaryotic Ogg1 proteins. Interestingly, plants possess both homologs but their relative contributions to repair remain uncertain. In this work we used Arabidopsis cell-free extracts monitor wild-type mutant plants. We found that FPG OGG1 catalyze excision cell a...

Active DNA demethylation in plants occurs through base excision repair, beginning with removal of methylated cytosine by the ROS1/DME subfamily 5-methylcytosine glycosylases. animals requires glycosylase TDG or MBD4, which functions after oxidation deamination 5-methylcytosine, respectively. However, little is known about steps following action active pathways and animals. We show here that Arabidopsis APE1L protein has apurinic/apyrimidinic endonuclease activities downstream ROS1 DME....

Six laccase genes, lcc1, lcc2, lcc3, lcc4, lcc5, and lcc9, of the vascular wilt fungus Fusarium oxysporum were isolated characterized. All genes have characteristic conserved domains for copper binding phenol oxidase enzymes. Targeted inactivation lcc5 resulted in a significant decrease extracellular activity. Reverse transcription-polymerase chain reaction showed that lcc9 constitutively expressed culture, whereas lcc3 appeared down up-regulated, respectively, by PacC. Oxidative stress...

Base excision repair (BER) is a critical pathway in cellular defense against endogenous or exogenous DNA damage. This elaborate multistep process initiated by glycosylases that excise the damaged base, and continues through concerted action of additional proteins finally restore to unmodified state. BER has been subject detailed biochemical analysis bacteria, yeast animals, mainly vitro reproduction entire reaction cell-free extracts. However, an understanding this plants consistently lagged...

Base excision repair (BER) is an essential cellular defence mechanism against DNA damage, but it poorly understood in plants. We used assay that monitors of damaged bases and abasic (apurinic/apyrimidinic, AP) sites Arabidopsis to characterize post-excision events during plant BER. found Apurinic endonuclease-redox protein (ARP) the major AP endonuclease activity cell extracts, required for incision uracil BER vitro. Mutant plants are deficient ARP grow normally hypersensitive...

Uracil in DNA arises by misincorporation of dUMP during replication and hydrolytic deamination cytosine. This common lesion is actively removed through a base excision repair (BER) pathway initiated uracil glycosylase (UDG) activity that excises the damage as free base. UDGs are classified into different families differentially distributed across eubacteria, archaea, yeast, animals, but remain to be unambiguously identified plants. We report here molecular characterization AtUNG (Arabidopsis...

Abstract Base excision repair (BER) generates gapped DNA intermediates containing a 5′-terminal 2-deoxyribose-5-phosphate (5′-dRP) group. In mammalian cells, gap filling and dRP removal are catalyzed by Pol β, which belongs to the X family of polymerases. higher plants, only member polymerases is λ. Although it generally believed that plant λ participates in BER, there limited experimental evidence for this hypothesis. Here we have characterized biochemical properties Arabidopsis thaliana...

DNA methylation patterns are the dynamic outcome of antagonist and demethylation mechanisms, but latter still poorly understood. Active in plants is mediated by a family glycosylases typified Arabidopsis ROS1 (repressor silencing 1). its homologs remove 5-methylcytosine incise sugar backbone at abasic site, thus initiating base excision repair pathway that finally inserts an unmethylated cytosine. The 3′-phosphatase ZDP processes some incision products generated ROS1, allowing subsequent...

Deoxyuridine triphosphatase (dUTPase) enzyme is an essential that protects DNA against uracil incorporation. No organism can tolerate the absence of this activity. In article, we show dUTPase function conserved between E. coli (Escherichia coli), yeast (Saccharomyces cerevisiae) and Arabidopsis (Arabidopsis thaliana) it in as both micro-organisms. Using a RNA interference strategy, plant lines were generated with diminished activity compared to wild-type. These plants are sensitive...

Significance Abasic (apurinic/apyrimidinic, AP) sites in DNA result from spontaneous and repair-mediated base release. They may be processed by AP endonucleases or lyases, but the relative roles of both types enzymes are poorly understood. Our study reveals that model plant Arabidopsis uses an lyase-dependent pathway to repair generated loss N7-methylguanine (N7-meG), a major lesion arising methylation damage. We further show main endonuclease is active on enzymatic excision N7-meG, not...

CLC-type voltage-gated chloride channels are a family of proteins which mediate transport across the plasma and intracellular membranes. A clc1 gene from vascular wilt fungus Fusarium oxysporum was characterized disrupted. The predicted Clc1 protein contained highly conserved transmembrane CBS domains this showed significant identities to Saccharomyces cerevisiae GEF1 Cryptococcus neoformans CLC-A channels. Inactivation caused deficiency in laccase activity more severe than that found any...

By controlling gene expression, DNA methylation contributes to key regulatory processes during plant development. Genomic patterns are dynamic and must be properly maintained and/or re-established upon replication active removal, therefore require sophisticated control mechanisms. Here we identify direct interplay between the repair factor damage-binding protein 2 (DDB2) ROS1-mediated demethylation pathway in Arabidopsis thaliana. We show that DDB2 forms a complex with ROS1 AGO4 they act at...

Plants are sessile organisms that need to cope with different conditions. The Base Excision Repair (BER) pathway is an important mechanism protecting the genome from DNA lesions. Apurinic/apyrimidinic (AP) endonucleases key BER enzymes process AP sites arising either spontaneously or as intermediates. In Arabidopsis there three endonucleases: AtARP1, AtAPE1L, and AtAPE2, in sugarcane two AtARP1 homologues have been identified: ScARP1 ScARP3. shares 59% sequence identity AtARP. Protein...

Abasic (apurinic/apyrimidinic, AP) sites are ubiquitous DNA lesions arising from spontaneous base loss and excision of damaged bases. They may be processed either by AP endonucleases or lyases, but the relative roles these two classes enzymes not well understood. We hypothesized that lyases differentially influenced sequence surrounding site and/or identity orphan base. To test this idea, we analysed activity plant human on substrates containing an abasic opposite G C in different contexts....