{"doi":"10.1016/j.jbc.2024.107461","title":"Dynamic stem–loop extension by Pol θ and templated insertion during DNA repair","abstract":"Theta-mediated end joining (TMEJ) is critical for survival of cancer cells when other DNA double-stranded break repair pathways are impaired. Human DNA polymerase theta (Pol θ) can extend ssDNA oligonucleotides, but little is known about preferred substrates and mechanism. We show that Pol θ can extend both ssDNA and RNA substrates by unimolecular stem-loop synthesis initiated by only two 3' terminal base pairs. Given sufficient time, Pol θ uses alternative pairing configurations that greatly expand the repertoire of sequence outcomes. Further primer-template adjustments yield low-fidelity outcomes when the nucleotide pool is imbalanced. Unimolecular stem-loop synthesis competes with bimolecular end joining, even when a longer terminal microhomology for end joining is available. Both reactions are partially suppressed by the ssDNA-binding protein replication protein A. Protein-primer grasp residues that are specific to Pol θ are needed for rapid stem-loop synthesis. The ability to perform stem-loop synthesis from a minimally paired primer is rare among human DNA polymerases, but we show that human DNA polymerases Pol η and Pol λ can catalyze related reactions. Using purified human Pol θ, we reconstituted in vitro TMEJ incorporating an insertion arising from a stem-loop extension. These activities may help explain TMEJ repair events that include inverted repeat sequences.","journal":"Journal of Biological Chemistry","year":2024,"id":436828,"datarank":0.37273599746820013,"base_score":2.4849066497880004,"endowment":2.4849066497880004,"self_citation_contribution":0.37273599746820013,"citation_network_contribution":0.0,"self_endowment_contribution":0.37273599746820013,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":11,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9562,"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":942070,"name":"Yuzhen Li","orcid":"0000-0003-4068-8316","position":1,"is_corresponding":false},{"id":1245644,"name":"Mark Returan","orcid":null,"position":2,"is_corresponding":false},{"id":511692,"name":"April M. Averill","orcid":null,"position":3,"is_corresponding":false},{"id":511255,"name":"Sylvie Doublié","orcid":"0000-0002-6294-5304","position":4,"is_corresponding":false},{"id":548571,"name":"Richard D. Wood","orcid":"0000-0002-9495-6892","position":5,"is_corresponding":false},{"id":934816,"name":"Denisse Carvajal-Maldonado","orcid":"0000-0001-9318-1207","position":0,"is_corresponding":true}],"reference_count":62,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-19T02:00:16.989773Z","pmid":"38876299","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":[]}