{"doi":"10.1128/aem.01370-14","title":"LacR Is a Repressor of\n            <i>lacABCD</i>\n            and LacT Is an Activator of\n            <i>lacTFEG</i>\n            , Constituting the\n            <i>lac</i>\n            Gene Cluster in Streptococcus pneumoniae","abstract":"<jats:title>ABSTRACT</jats:title>\n          <jats:p>\n            Comparison of the transcriptome of\n            <jats:named-content content-type=\"genus-species\">Streptococcus pneumoniae</jats:named-content>\n            strain D39 grown in the presence of either lactose or galactose with that of the strain grown in the presence of glucose revealed the elevated expression of various genes and operons, including the\n            <jats:italic>lac</jats:italic>\n            gene cluster, which is organized into two operons, i.e.,\n            <jats:italic>lac</jats:italic>\n            operon I (\n            <jats:italic>lacABCD</jats:italic>\n            ) and\n            <jats:italic>lac</jats:italic>\n            operon II (\n            <jats:italic>lacTFEG</jats:italic>\n            ). Deletion of the DeoR family transcriptional regulator\n            <jats:italic>lacR</jats:italic>\n            that is present downstream of the\n            <jats:italic>lac</jats:italic>\n            gene cluster revealed elevated expression of\n            <jats:italic>lac</jats:italic>\n            operon I even in the absence of lactose. This suggests a function of LacR as a transcriptional repressor of\n            <jats:italic>lac</jats:italic>\n            operon I, which encodes enzymes involved in the phosphorylated tagatose pathway in the absence of lactose or galactose. Deletion of\n            <jats:italic>lacR</jats:italic>\n            did not affect the expression of\n            <jats:italic>lac</jats:italic>\n            operon II, which encodes a lactose-specific phosphotransferase. This finding was further confirmed by β-galactosidase assays with P\n            <jats:italic>lacA-lacZ</jats:italic>\n            and P\n            <jats:italic>lacT-lacZ</jats:italic>\n            in the presence of either lactose or glucose as the sole carbon source in the medium. This suggests the involvement of another transcriptional regulator in the regulation of\n            <jats:italic>lac</jats:italic>\n            operon II, which is the BglG-family transcriptional antiterminator LacT. We demonstrate the role of LacT as a transcriptional activator of\n            <jats:italic>lac</jats:italic>\n            operon II in the presence of lactose and CcpA-independent regulation of the\n            <jats:italic>lac</jats:italic>\n            gene cluster in\n            <jats:named-content content-type=\"genus-species\">S. pneumoniae</jats:named-content>\n            .\n          </jats:p>","journal":"Applied and Environmental Microbiology","year":2014,"id":40478,"datarank":1.1506747803019155,"base_score":3.5263605246161616,"endowment":3.5263605246161616,"self_citation_contribution":0.5289540786924243,"citation_network_contribution":0.6217207016094912,"self_endowment_contribution":0.5289540786924243,"citer_contribution":0.6217207016094912,"corpus_percentile":null,"corpus_rank":null,"citation_count":33,"citer_count":18,"citers_with_citation_signal":16,"citers_with_endowment":16,"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":196598,"name":"Sulman Shafeeq","orcid":null,"position":1,"is_corresponding":false},{"id":160605,"name":"Oscar P. Kuipers","orcid":null,"position":2,"is_corresponding":false},{"id":169368,"name":"Muhammad Afzal","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":"24951784","pmcid":"PMC4136080","openalex_id":"https://openalex.org/W2130074982","authors":[],"funders":[],"total_grants":0,"fwci":3.8825,"citation_percentile":0.9368846,"influential_citations":0,"citation_trend":[{"year":2014,"count":1},{"year":2015,"count":10},{"year":2016,"count":4},{"year":2017,"count":3},{"year":2018,"count":2},{"year":2020,"count":1},{"year":2021,"count":5},{"year":2022,"count":1},{"year":2023,"count":2},{"year":2024,"count":3},{"year":2025,"count":1}],"oa_status":"bronze","license":"https://journals.asm.org/non-commercial-tdm-license","oa_locations":[{"url":"https://aem.asm.org/content/aem/80/17/5349.full.pdf","host_type":"journal"},{"url":"https://aem.asm.org/content/aem/80/17/5349.full.pdf","host_type":"publisher"},{"url":"https://journals.asm.org/doi/pdf/10.1128/AEM.01370-14","host_type":"publisher"},{"url":"https://doi.org/10.1128/aem.01370-14","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/24951784","host_type":"repository"},{"url":"https://research.rug.nl/en/publications/de4c481e-fbdc-4eca-8239-93d4b72e0fe3","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/4136080","host_type":"repository"},{"url":"https://hdl.handle.net/11370/de4c481e-fbdc-4eca-8239-93d4b72e0fe3","host_type":"repository"}],"fields_of_study":["Pneumonia and Respiratory Infections","Neonatal and Maternal Infections","Streptococcal Infections and Treatments","Culture Media","Galactose","Gene Deletion","Gene Expression Regulation, Bacterial","Glucose","Lac Operon","Lac Repressors","Lactose","Multigene Family","Promoter Regions, Genetic","Streptococcus pneumoniae","Trans-Activators"],"mesh_terms":["Culture Media","Galactose","Multigene Family","Glucose","Lac Operon","Lactose","Promoter Regions, Genetic","Streptococcus pneumoniae","Trans-Activators","Gene Expression Regulation, Bacterial","Gene Deletion","Lac Repressors"],"keywords":["Streptococcus pneumoniae","Repressor","Microbiology","Gene cluster","Activator (genetics)","Lac repressor","lac operon","Biology","Gene","Bacteria","Molecular biology","Genetics","Plasmid","Gene expression"],"sdg_mappings":[],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[{"name":"geo"}],"source":"live","citation_network_status":"fetched"},"created_at":"2026-06-12T06:32:18.402746Z","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":[]}