{"doi":"10.1016/j.jcf.2025.09.006","title":"Identity, functional consequences, and context effects of amino acids inserted during suppression of CFTR nonsense mutations","abstract":"BACKGROUND: Cystic fibrosis patients who carry a CFTR nonsense allele often express negligible CFTR protein, and thus, are unresponsive to CFTR modulators. Nonsense suppression (also called readthrough) is an emerging therapeutic approach for this patient subgroup that uses small molecules to suppress translation termination at in-frame premature termination codons (PTCs) and rescue full-length, functional CFTR protein. This study examines mechanistic aspects of readthrough at six CFTR PTCs commonly found in CF patients. METHODS: CFTR expression and chloride conductance were used to assess the responsiveness of six different CFTR PTCs to G418-mediated readthrough. LC-MS/MS was used to identify the CFTR variant proteins generated by readthrough of PTCs in their native, local CFTR mRNA sequence context. For each CFTR variant protein identified, the abundance, processing, activity, and responsiveness to CFTR modulators were characterized. RESULTS: CFTR expression and function varied widely among PTCs, with UGA generally being the most responsive to G418-mediated readthrough. The amino acids incorporated at PTCs during G418-induced readthrough also varied, depending on the PTC and its surrounding local mRNA context. Modulators stabilized and enhanced the abundance and activity of most CFTR variant proteins generated by PTC readthrough, with many variant proteins reaching WT CFTR activity. CONCLUSIONS: Nonsense suppression therapy shows promise as a treatment for CF patients who carry a PTC, especially when combined with current CFTR modulators. Mechanistic insights of readthrough gleaned from this study can be used to develop better therapeutic strategies for treating CF patients who carry a nonsense mutation.","journal":"Journal of Cystic Fibrosis","year":2025,"id":526999,"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":0.9578,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":631075,"name":"Jianguo Chen","orcid":"0000-0003-0424-1875","position":1,"is_corresponding":false},{"id":429080,"name":"Lianwu Fu","orcid":null,"position":2,"is_corresponding":false},{"id":733851,"name":"D. Woodrow Benson","orcid":"0000-0002-1134-1973","position":3,"is_corresponding":false},{"id":1403128,"name":"Jenna Ekstrom","orcid":"0009-0003-2131-4383","position":4,"is_corresponding":false},{"id":430452,"name":"Audra A. Hargett","orcid":"0000-0002-0459-1392","position":5,"is_corresponding":false},{"id":424893,"name":"Matthew B. Renfrow","orcid":"0000-0002-4193-7305","position":6,"is_corresponding":false},{"id":263850,"name":"Steven M. Rowe","orcid":"0000-0001-9045-0133","position":7,"is_corresponding":false},{"id":380669,"name":"Kim M. Keeling","orcid":"0000-0003-0471-5858","position":8,"is_corresponding":false},{"id":631078,"name":"David M. Bedwell","orcid":"0000-0002-6605-818X","position":9,"is_corresponding":false},{"id":631076,"name":"K. Thrasher","orcid":"0000-0003-0281-1686","position":0,"is_corresponding":true}],"reference_count":48,"raw_metadata":null,"created_at":"2026-07-19T02:50:34.851930Z","pmid":"41015699","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":[]}