{"doi":"10.17615/aftx-3z93","title":"A Chimeric Virus-Mouse Model System for Evaluating the Function and Inhibition of Papain-Like Proteases of Emerging Coronaviruses","abstract":"To combat emerging coronaviruses, developing safe and efficient platforms to evaluate viral protease activities and the efficacy of protease inhibitors is a high priority. Here, we exploit a biosafety level 2 (BSL-2) chimeric Sindbis virus system to evaluate protease activities and the efficacy of inhibitors directed against the papain-like protease (PLpro) of severe acute respiratory syndrome coronavirus (SARS-CoV), a biosafety level 3 (BSL-3) pathogen. We engineered Sindbis virus to coexpress PLpro and a substrate, murine interferon-stimulated gene 15 (ISG15), and found that PLpro mediates removal of ISG15 (deISGylation) from cellular proteins. Mutation of the catalytic cysteine residue of PLpro or addition of a PLpro inhibitor blocked deISGylation in virus-infected cells. Thus, deISGylation is a marker of PLpro activity. Infection of alpha/beta interferon receptor knockout (IFNAR−/−) mice with these chimeric viruses revealed that PLpro deISGylation activity removed ISG15-mediated protection during viral infection. Importantly, administration of a PLpro inhibitor protected these mice from lethal infection, demonstrating the efficacy of a coronavirus protease inhibitor in a mouse model. However, this PLpro inhibitor was not sufficient to protect the mice from lethal infection with SARS-CoV MA15, suggesting that further optimization of the delivery and stability of PLpro inhibitors is needed. We extended the chimeric-virus platform to evaluate the papain-like protease/deISGylating activity of Middle East respiratory syndrome coronavirus (MERS-CoV) to provide a small-animal model to evaluate PLpro inhibitors of this recently emerged pathogen. This platform has the potential to be universally adaptable to other viral and cellular enzymes that have deISGylating activities.","journal":"UNC Libraries","year":2020,"id":144499,"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":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9424,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":274234,"name":"Deborah J. Lenschow","orcid":"0000-0002-9400-5309","position":1,"is_corresponding":false},{"id":418118,"name":"Scott D. Larsen","orcid":"0000-0001-8440-4990","position":2,"is_corresponding":false},{"id":5952,"name":"Ralph S. Baric","orcid":"0000-0001-6827-8701","position":3,"is_corresponding":false},{"id":612957,"name":"Sarah E. St. John","orcid":"0000-0001-6564-7081","position":4,"is_corresponding":false},{"id":612958,"name":"Daniel Brian Nichols","orcid":"0000-0002-5477-9801","position":5,"is_corresponding":false},{"id":77531,"name":"Susan C. Baker","orcid":"0000-0001-6485-8143","position":6,"is_corresponding":false},{"id":536698,"name":"Michael W. Wilson","orcid":"0009-0004-8618-9226","position":7,"is_corresponding":false},{"id":107929,"name":"Andrew D. Mesecar","orcid":"0000-0002-1241-2577","position":8,"is_corresponding":false},{"id":233693,"name":"Xufang Deng","orcid":"0000-0002-7604-3627","position":9,"is_corresponding":false},{"id":300195,"name":"Sudhakar Agnihothram","orcid":null,"position":10,"is_corresponding":false},{"id":496832,"name":"Anna M. Mielech","orcid":null,"position":0,"is_corresponding":true}],"reference_count":0,"raw_metadata":null,"created_at":"2026-07-18T23:17:45.339291Z","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":[]}