{"doi":"10.1101/2022.09.27.509796","title":"Yeast mtDNA transcription initiation in single nucleotide addition steps","abstract":"Abstract Transcription initiation catalyzed by the RNA polymerase is a multistep process involving promoter binding, transcription bubble formation, abortive RNA synthesis, and transition into elongation following promoter escape. We report cryo-EM structures of yeast mitochondrial RNA polymerase initiation complexes (ICs) with transcription factor MTF1 catalyzing RNA synthesis from de novo initiation to 6-mer synthesis at single-nucleotide steps on fully-resolved transcription bubbles. The growing RNA:DNA hybrid is accommodated by continuous scrunching of the template strand while the non-template and MTF1 C-tail in the polymerase cleft are structurally reorganized. Each nucleotide addition accumulates stress energy, which drives abortive RNA synthesis during early transcription initiation steps and promoter release later. The non-template scrunches as loops in IC2/IC3, and unscrunching assists abortive synthesis of 2-/3-mer RNAs. Subsequently, in IC5 and IC6, the non-template strand assumes a stable structure by stacking its bases into a spiral staircase-like structure that supports processive synthesis. In IC6, the template scrunches to the maximum and places the -1 nucleotide in a pocket near the thumb domain. Subsequently, the -1 nucleotide acts as a pivot point for promoter escape ushering the IC into the elongation phase. The structural snapshots visualize the interplay between abortive and productive synthesis regulating transcription initiation.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2022,"id":311663,"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":0.9541,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":364377,"name":"Jiayu Shen","orcid":"0000-0001-8447-9378","position":1,"is_corresponding":false},{"id":364374,"name":"Brent De Wijngaert","orcid":"0000-0002-7551-8897","position":2,"is_corresponding":false},{"id":1007752,"name":"Urmimala Basu","orcid":"0000-0003-4035-1246","position":3,"is_corresponding":false},{"id":364381,"name":"Smita S. Patel","orcid":"0000-0002-2523-4933","position":4,"is_corresponding":false},{"id":364382,"name":"Kalyan Das","orcid":"0000-0002-8897-324X","position":5,"is_corresponding":false},{"id":1007751,"name":"Quinten Goovaerts","orcid":"0000-0002-2168-1103","position":0,"is_corresponding":true}],"reference_count":52,"raw_metadata":null,"created_at":"2026-07-19T00:33:32.327694Z","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":[]}