{"doi":"10.1111/j.1365-2958.1994.tb00298.x","title":"Genetic characterization of a <i>Rhizobium meliloti</i> lactose utilization locus","abstract":"<jats:title>Summary</jats:title><jats:p>We identified several linked genes of a lactose regulon in <jats:italic>Rhizobium meliloti.</jats:italic> These were <jats:italic>lacZ</jats:italic>, the structural gene for β‐galactosidase; <jats:italic>lacR</jats:italic>, the lactose repressor gene; and two genes encoding proteins of unknown function. <jats:italic>lacW</jats:italic> and <jats:italic>lacX.</jats:italic> Insertion mutants in <jats:italic>lacW</jats:italic> and <jats:italic>lacZ</jats:italic> belonged to a single genetic compiementation group, and <jats:italic>lacW</jats:italic> appeared to lie upstream of <jats:italic>lacZ</jats:italic> in an operon. Expression of <jats:italic>lacZ, lacW</jats:italic> and <jats:italic>lacX</jats:italic> was repressed by <jats:italic>lacR</jats:italic>, and expression of <jats:italic>lacZ</jats:italic> and <jats:italic>lacW</jats:italic> was derepressed by lactose. <jats:italic>lacZ</jats:italic> was not required for Induction of <jats:italic>lacW by</jats:italic> lactose, suggesting that lactose itself, rather than a processed form of lactose, may be the actual Inducer molecule. Expression of all three genes was repressed by succinate, and the <jats:italic>lacR</jats:italic> independence of this repression showed that inducer exciusion could not be the sole mechanism. This pattern of <jats:italic>lac</jats:italic> gene organization and regulation differs in several ways from that observed in enteric bacteria.</jats:p>","journal":"Molecular Microbiology","year":1994,"id":17521,"datarank":1.0387805018247112,"base_score":2.8903717578961645,"endowment":2.8903717578961645,"self_citation_contribution":0.4335557636844247,"citation_network_contribution":0.6052247381402865,"self_endowment_contribution":0.4335557636844247,"citer_contribution":0.6052247381402865,"corpus_percentile":null,"corpus_rank":null,"citation_count":17,"citer_count":17,"citers_with_citation_signal":13,"citers_with_endowment":13,"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":125054,"name":"John A. 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Jelesko","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"base_score":2.8903717578961645,"endowment":2.8903717578961645,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"8145640","pmcid":null,"openalex_id":"https://openalex.org/W1979036052","authors":[],"funders":[{"funder_name":"NICHD NIH HHS","grant_id":"2T32HD07183","title":null},{"funder_name":"NIGMS NIH HHS","grant_id":"GM39785","title":null}],"total_grants":2,"fwci":1.142,"citation_percentile":0.80056636,"influential_citations":1,"citation_trend":[{"year":2014,"count":2},{"year":2016,"count":1},{"year":2017,"count":2},{"year":2026,"count":1}],"oa_status":"closed","license":"http://onlinelibrary.wiley.com/termsAndConditions#vor","oa_locations":[{"url":"https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2958.1994.tb00298.x","host_type":"publisher"},{"url":"https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2958.1994.tb00298.x","host_type":"publisher"},{"url":"https://doi.org/10.1111/j.1365-2958.1994.tb00298.x","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/8145640","host_type":"repository"}],"fields_of_study":["Legume Nitrogen Fixing Symbiosis","Plant nutrient uptake and metabolism","Cassava research and cyanide","Biology","Medicine","Environmental Science","DNA Transposable Elements","Gene Expression Regulation, Bacterial","Genetic Complementation Test","Lac Operon","Lactose","Mutagenesis, Insertional","Mutagenesis, Site-Directed","Recombinant Fusion Proteins","Restriction Mapping","Sinorhizobium meliloti","Succinates","Succinic Acid","Transduction, Genetic","beta-Galactosidase"],"mesh_terms":["beta-Galactosidase","DNA Transposable Elements","Genetic Complementation Test","Lac Operon","Lactose","Recombinant Fusion Proteins","Succinates","Transduction, Genetic","Restriction Mapping","Gene Expression Regulation, Bacterial","Mutagenesis, Insertional","Mutagenesis, Site-Directed","Sinorhizobium meliloti","Succinic Acid"],"keywords":["lac operon","Biology","Inducer","Lac repressor","Lactose","Regulon","Repressor","Operon","Gene","Regulator gene","Mutant","Beta-galactosidase","Genetics","Psychological repression","Rhizobium","Regulation of gene expression","Gene expression","Biochemistry"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Reduced inequalities"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-06-02T19:13:35.404153Z","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":[]}