{"doi":"10.1046/j.1365-2958.2003.03440.x","title":"A new <i>Schizosaccharomyces pombe</i> base excision repair mutant, <i>nth1</i>, reveals overlapping pathways for repair of DNA base damage","abstract":"<jats:title>Summary</jats:title><jats:p>Endonuclease III (Nth) enzyme from <jats:italic>Escherichia coli</jats:italic> is involved in base excision repair of oxidised pyrimidine residues in DNA. The <jats:italic>Schizosaccharomyces pombe</jats:italic> Nth1 protein is a sequence and functional homologue of <jats:italic>E. coli</jats:italic> Nth, possessing both DNA glycosylase and apurinic/apyrimidinic (AP) lyase activity. Here, we report the construction and characterization of the <jats:italic>S. pombe nth1</jats:italic> mutant. The <jats:italic>nth1</jats:italic> mutant exhibited no enhanced sensitivity to oxidising agents, UV or γ‐irradiation, but was hypersensitive to the alkylating agent methyl methanesulphonate (MMS). Analysis of base excision from DNA exposed to [<jats:sup>3</jats:sup>H]methyl‐<jats:italic>N</jats:italic>‐nitrosourea showed that the purified Nth1 enzyme did not remove alkylated bases such as 3‐methyladenine and 7‐methylguanine whereas methyl‐formamidopyrimidine was excised efficiently. The repair of AP sites in <jats:italic>S. pombe</jats:italic> has previously been shown to be independent of Apn1‐like AP endonuclease activity, and the main reason for the MMS sensitivity of <jats:italic>nth1</jats:italic> cells appears   to   be   their   lack   of   AP   lyase   activity.   The <jats:italic>nth1</jats:italic> mutant   also   exhibited   elevated   frequencies   of spontaneous mitotic intrachromosomal recombination,   which   is   a   phenotype   shared   by   the   MMS‐hypersensitive DNA repair mutants <jats:italic>rad2</jats:italic>, <jats:italic>rhp55</jats:italic> and NER repair mutants <jats:italic>rad16</jats:italic>, <jats:italic>rhp14, rad13</jats:italic> and <jats:italic>swi10</jats:italic>. Epistasis analyses of <jats:italic>nth1</jats:italic> and these DNA repair mutants suggest that several DNA damage repair/tolerance pathways participate in the processing of alkylation and spontaneous DNA damage in <jats:italic>S. pombe</jats:italic>.</jats:p>","journal":"Molecular Microbiology","year":2003,"id":36296,"datarank":1.535897563895499,"base_score":3.5263605246161616,"endowment":3.5263605246161616,"self_citation_contribution":0.5289540786924243,"citation_network_contribution":1.0069434852030748,"self_endowment_contribution":0.5289540786924243,"citer_contribution":1.0069434852030748,"corpus_percentile":null,"corpus_rank":null,"citation_count":33,"citer_count":28,"citers_with_citation_signal":26,"citers_with_endowment":26,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":183247,"name":"Magnar Bjørås","orcid":null,"position":1,"is_corresponding":false},{"id":184152,"name":"Ingrun Alseth","orcid":null,"position":2,"is_corresponding":false},{"id":184153,"name":"Ingrid Morland","orcid":null,"position":3,"is_corresponding":false},{"id":184154,"name":"S. McCready","orcid":null,"position":4,"is_corresponding":false},{"id":183245,"name":"Erling Seeberg","orcid":null,"position":5,"is_corresponding":false},{"id":184155,"name":"Irina Tsaneva","orcid":null,"position":6,"is_corresponding":false},{"id":184151,"name":"Fekret Osman","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"base_score":3.5263605246161616,"endowment":3.5263605246161616,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"12675805","pmcid":null,"openalex_id":"https://openalex.org/W1795982142","authors":[],"funders":[],"total_grants":0,"fwci":1.0308,"citation_percentile":0.73352747,"influential_citations":4,"citation_trend":[{"year":2012,"count":2},{"year":2014,"count":1},{"year":2015,"count":1},{"year":2016,"count":2},{"year":2018,"count":1},{"year":2020,"count":2},{"year":2021,"count":1},{"year":2023,"count":4}],"oa_status":"closed","license":"http://onlinelibrary.wiley.com/termsAndConditions#vor","oa_locations":[{"url":"https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1365-2958.2003.03440.x","host_type":"publisher"},{"url":"https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2958.2003.03440.x","host_type":"publisher"},{"url":"https://doi.org/10.1046/j.1365-2958.2003.03440.x","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/12675805","host_type":"repository"}],"fields_of_study":["DNA Repair Mechanisms","Cancer therapeutics and mechanisms","DNA and Nucleic Acid Chemistry","Biology","Medicine","Cell Survival","DNA Damage","DNA Glycosylases","DNA Repair","DNA, Fungal","Deoxyribonuclease (Pyrimidine Dimer)","Escherichia coli Proteins","Fungal Proteins","Methyl Methanesulfonate","Microbial Sensitivity Tests","Mutagens","Mutation","Pyrimidines","Recombination, Genetic","Schizosaccharomyces","Ultraviolet Rays"],"mesh_terms":["Cell Survival","DNA Damage","DNA Repair","DNA, Fungal","Fungal Proteins","Methyl Methanesulfonate","Microbial Sensitivity Tests","Mutagens","Mutation","Pyrimidines","Recombination, Genetic","Schizosaccharomyces","Ultraviolet Rays","Escherichia coli Proteins","Deoxyribonuclease (Pyrimidine Dimer)","DNA Glycosylases"],"keywords":["DNA glycosylase","Schizosaccharomyces pombe","AP site","Biology","Base excision repair","DNA repair","Nucleotide excision repair","Schizosaccharomyces","AP endonuclease","DNA damage","Endonuclease","Methyl methanesulfonate","Molecular biology","Mutant","DNA-(apurinic or apyrimidinic site) lyase","DNA","Biochemistry","Gene"],"sdg_mappings":[],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-06-10T15:26:53.461555Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}