{"doi":"10.1261/rna.079933.123","title":"Inefficient recruitment of DDX39B impedes pre-spliceosome assembly on FOXP3 introns","abstract":"Forkhead box P3 (FOXP3) is the master fate-determining transcription factor in regulatory T (Treg) cells and is essential for their development, function and homeostasis. Mutations in FOXP3 cause immunodysregulation polyendocrinopathy enteropathy X-linked (IPEX) syndrome, and aberrant expression of FOXP3 has been implicated in other diseases such as multiple sclerosis and cancer. We previously demonstrated that pre-mRNA splicing of FOXP3 RNAs is highly sen-sitive to levels of DExD-box polypeptide 39B (DDX39B) and here we investigate the mechanism of this sensitivity. FOXP3 introns have cytidine (C)-rich/uridine (U)-poor polypyrimidine (py) tracts that are responsible for their inefficient splicing and confer sensitivity to DDX39B. We show that there is a deficiency in the assembly of commitment complexes (CCs) on FOXP3 introns, which is consistent with the lower affinity of U2AF2 for C-rich/U-poor py tracts. Our data indicate an even stronger effect on the conversion of CCs to pre-spliceosomes. We propose that this is due to an altered conformation that U2AF2 adopts when it binds to C-rich/U-poor py tracts and that this conformation has a lower affinity for DDX39B. As a consequence, CCs assembled on FOXP3 introns are defective in recruiting DDX39B and this leads to inefficient assembly of pre-spliceosome complexes.","journal":"RNA","year":2024,"id":475600,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":3,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9583,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":707618,"name":"Aaron O. Bailey","orcid":"0000-0001-8063-3032","position":1,"is_corresponding":false},{"id":250363,"name":"William K. Russell","orcid":"0000-0003-1931-4555","position":2,"is_corresponding":false},{"id":232721,"name":"Mariano A. García-Blanco","orcid":"0000-0001-8538-1997","position":3,"is_corresponding":false},{"id":698963,"name":"Chloe K. Nagasawa","orcid":"0000-0002-4550-1381","position":0,"is_corresponding":true}],"reference_count":54,"raw_metadata":null,"created_at":"2026-07-19T02:06:21.071690Z","pmid":"38575347","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":[]}