{"doi":"10.1128/msphere.00438-25","title":"TgAP2X-7 is a novel cell cycle-regulated transcription factor that plays an essential role in\n                    <i>Toxoplasma</i>\n                    tachyzoite propagation","abstract":"<jats:title>ABSTRACT</jats:title>\n                  <jats:sec>\n                    <jats:title/>\n                    <jats:p>\n                      Apicomplexan AP2 (ApiAP2) family proteins are a family of transcription factors that are known to regulate gene expression in apicomplexan pathogens, including\n                      <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                      . In this study, we focused on TgAP2X-7, a member of the APiAP2 family that is predicted to be essential for\n                      <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                      fitness. Endogenous tagging of TgAP2X-7 followed by immunofluorescence analysis revealed that it’s a cell cycle-regulated nuclear protein with peak expression in the G1 phase. Since TgAP2X-7 is predicted to be essential for parasite growth, we adopted an auxin-inducible degron (AID) based conditional knockdown approach to understand its function. Phenotypic analysis of the conditional knockdown mutant of TgAP2X-7 showed that the protein is indeed essential for\n                      <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                      propagation\n                      <jats:italic toggle=\"yes\">in vitro,</jats:italic>\n                      and loss of this transcription factor results in a major defect in invasion and a minor defect in replication. Examination with cell division markers indicated that the absence of TgAP2X-7 results in defects in endodyogeny. Transcriptomic analysis indicated that loss of TgAP2X-7 leads to dysregulation of global gene expression in the parasite, including genes required for host-cell invasion, metabolism, and gene expression. Additionally, Cleavage Under Targets and Tagmentation (CUT&amp;TAG) analysis suggests that TgAP2X-7 likely binds to an 11 bp motif [C/T/G]GCATGCA[G/C/A][C/T/G][G/A] in the parasite genes’ promoter region. Together, these findings suggest that TgAP2X-7 is a novel transcriptional regulator in\n                      <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                      that governs the expression of genes required for parasite propagation.\n                    </jats:p>\n                    <jats:sec>\n                      <jats:title>IMPORTANCE</jats:title>\n                      <jats:p>\n                        <jats:italic toggle=\"yes\">Toxoplasma gondii</jats:italic>\n                        is a protozoan parasite that can cause life-threatening disease in mammals; hence, identifying key factors required for parasite growth and pathogenesis is important to develop novel therapeutics. In this study, we identify and characterize a member of the Apicomplexan AP2 (ApiAP2) family, TgAP2X-7, a developmentally regulated transcription factor. By generating conditional mutant TgAP2X-7, we show that this protein is required for\n                        <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                        propagation\n                        <jats:italic toggle=\"yes\">in vitro,</jats:italic>\n                        and the absence of this protein results in parasites with significantly reduced competency in invasion, moderate deficiency in replication, and defects in cell division. Importantly, TgAP2X-7-deficient parasites show global changes in gene expression profile, including decreased expression of genes important for\n                        <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                        entry into the host cell. Additionally, we identified an 11 bp DNA motif likely recognized by this transcription factor. Hence, this study provides an initial insight into the function of a novel cell cycle-regulated transcription factor essential for\n                        <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                        growth.\n                      </jats:p>\n                    </jats:sec>\n                  </jats:sec>","journal":"mSphere","year":2025,"id":651732,"datarank":0.10397207708399181,"base_score":0.6931471805599453,"endowment":0.6931471805599453,"self_citation_contribution":0.10397207708399181,"citation_network_contribution":0.0,"self_endowment_contribution":0.10397207708399181,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":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":390804,"name":"Ramu Anandakrishnan","orcid":"0000-0003-0422-3984","position":1,"is_corresponding":false},{"id":1106771,"name":"Rajshekhar Y. Gaji","orcid":"0000-0002-9505-2123","position":2,"is_corresponding":false},{"id":1699865,"name":"Padmaja Mandadi","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"TgAP2X-7 is a novel cell cycle-regulated transcription factor that plays an essential role in\n                    <i>Toxoplasma</i>\n                    tachyzoite propagation","abstract":"<jats:title>ABSTRACT</jats:title>\n                  <jats:sec>\n                    <jats:title/>\n                    <jats:p>\n                      Apicomplexan AP2 (ApiAP2) family proteins are a family of transcription factors that are known to regulate gene expression in apicomplexan pathogens, including\n                      <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                      . In this study, we focused on TgAP2X-7, a member of the APiAP2 family that is predicted to be essential for\n                      <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                      fitness. Endogenous tagging of TgAP2X-7 followed by immunofluorescence analysis revealed that it’s a cell cycle-regulated nuclear protein with peak expression in the G1 phase. Since TgAP2X-7 is predicted to be essential for parasite growth, we adopted an auxin-inducible degron (AID) based conditional knockdown approach to understand its function. Phenotypic analysis of the conditional knockdown mutant of TgAP2X-7 showed that the protein is indeed essential for\n                      <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                      propagation\n                      <jats:italic toggle=\"yes\">in vitro,</jats:italic>\n                      and loss of this transcription factor results in a major defect in invasion and a minor defect in replication. Examination with cell division markers indicated that the absence of TgAP2X-7 results in defects in endodyogeny. Transcriptomic analysis indicated that loss of TgAP2X-7 leads to dysregulation of global gene expression in the parasite, including genes required for host-cell invasion, metabolism, and gene expression. Additionally, Cleavage Under Targets and Tagmentation (CUT&amp;TAG) analysis suggests that TgAP2X-7 likely binds to an 11 bp motif [C/T/G]GCATGCA[G/C/A][C/T/G][G/A] in the parasite genes’ promoter region. Together, these findings suggest that TgAP2X-7 is a novel transcriptional regulator in\n                      <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                      that governs the expression of genes required for parasite propagation.\n                    </jats:p>\n                    <jats:sec>\n                      <jats:title>IMPORTANCE</jats:title>\n                      <jats:p>\n                        <jats:italic toggle=\"yes\">Toxoplasma gondii</jats:italic>\n                        is a protozoan parasite that can cause life-threatening disease in mammals; hence, identifying key factors required for parasite growth and pathogenesis is important to develop novel therapeutics. In this study, we identify and characterize a member of the Apicomplexan AP2 (ApiAP2) family, TgAP2X-7, a developmentally regulated transcription factor. By generating conditional mutant TgAP2X-7, we show that this protein is required for\n                        <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                        propagation\n                        <jats:italic toggle=\"yes\">in vitro,</jats:italic>\n                        and the absence of this protein results in parasites with significantly reduced competency in invasion, moderate deficiency in replication, and defects in cell division. Importantly, TgAP2X-7-deficient parasites show global changes in gene expression profile, including decreased expression of genes important for\n                        <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                        entry into the host cell. Additionally, we identified an 11 bp DNA motif likely recognized by this transcription factor. Hence, this study provides an initial insight into the function of a novel cell cycle-regulated transcription factor essential for\n                        <jats:italic toggle=\"yes\">Toxoplasma</jats:italic>\n                        growth.\n                      </jats:p>\n                    </jats:sec>\n                  </jats:sec>","is_dataset_classified":null,"base_score":0.0,"endowment":0.0,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"40920096","pmcid":"PMC12482157","openalex_id":null,"authors":[],"funders":[{"funder_name":"National Institute of Allergy and Infectious Diseases","grant_id":"1R21AI162606","title":null},{"funder_name":"NIAID NIH HHS","grant_id":"R21 AI162606","title":null},{"funder_name":"National Institutes of Health","grant_id":"5R21AI162606-02","title":"Exploring the function of a novel tyrosine kinase like (TKL) protein in Toxoplasma endodyogeny"}],"total_grants":3,"fwci":null,"citation_percentile":null,"influential_citations":0,"citation_trend":[],"oa_status":"gold","license":"cc-by","oa_locations":[{"url":"https://doi.org/10.1128/msphere.00438-25","host_type":"publisher"},{"url":"https://journals.asm.org/doi/pdf/10.1128/msphere.00438-25","host_type":"publisher"},{"url":"https://doaj.org/article/61ad0e098a4341f9b6097bfb31984a41","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/12482157","host_type":"repository"},{"url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC12482157/","host_type":"repository"},{"url":"https://europepmc.org/articles/PMC12482157","host_type":"Europe_PMC"},{"url":"https://europepmc.org/articles/PMC12482157?pdf=render","host_type":"Europe_PMC"},{"url":"https://pubmed.ncbi.nlm.nih.gov/40920096","host_type":""},{"url":"https://pubmed.ncbi.nlm.nih.gov/40920096/","host_type":""}],"fields_of_study":["0303 health sciences","03 medical and health sciences"],"mesh_terms":["Animals","Humans","Toxoplasma","Protozoan Proteins","Transcription Factors","Gene Expression Profiling","Cell Cycle","Gene Expression Regulation"],"keywords":["Transcription factors","Toxoplasma gondii","Parasitology","Apicomplexan Parasites","Gene Expression Regulation","Gene Expression Profiling","Cell Cycle","Protozoan Proteins","Humans","Animals","Toxoplasma","Research Article"],"sdg_mappings":[],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[{"name":"doi"}],"source":"live","citation_network_status":"fetched"},"created_at":"2026-08-10T10:32:43.691050Z","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":[]}