DNA-directed RNA polymerases II and IV subunit 5A / RNA-dependent RNA polymerase 2 / DNA-directed RNA polymerases II, IV and V subunit 11 / DNA-directed RNA polymerases II, IV and V subunit 3 / DNA-directed RNA polymerases IV and V subunit 4 / DNA-directed RNA polymerases II, IV and V subunit 9A / DNA-directed RNA polymerase IV subunit 7 / DNA-directed RNA polymerases II, IV and V subunit 10 / DNA-directed RNA polymerases II, IV and V subunit 6A / DNA-directed RNA polymerases II, IV and V subunit 12 ...DNA-directed RNA polymerases II and IV subunit 5A / RNA-dependent RNA polymerase 2 / DNA-directed RNA polymerases II, IV and V subunit 11 / DNA-directed RNA polymerases II, IV and V subunit 3 / DNA-directed RNA polymerases IV and V subunit 4 / DNA-directed RNA polymerases II, IV and V subunit 9A / DNA-directed RNA polymerase IV subunit 7 / DNA-directed RNA polymerases II, IV and V subunit 10 / DNA-directed RNA polymerases II, IV and V subunit 6A / DNA-directed RNA polymerases II, IV and V subunit 12 / DNA-directed RNA polymerases IV and V subunit 2 / DNA-directed RNA polymerase IV subunit 1 / DNA-directed RNA polymerases II, IV and V subunit 8B 類似検索 - 構成要素
National Natural Science Foundation of China (NSFC)
中国
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ジャーナル: Sci Adv / 年: 2024 タイトル: Transcription elongation of the plant RNA polymerase IV is prone to backtracking. 著者: Chengli Fang / Kun Huang / Xiaoxian Wu / Hongwei Zhang / Zhanxi Gu / Jiawei Wang / Yu Zhang / 要旨: RNA polymerase IV (Pol IV) forms a complex with RNA-directed RNA polymerase 2 (RDR2) to produce double-stranded RNA (dsRNA) precursors essential for plant gene silencing. In the "backtracking- ...RNA polymerase IV (Pol IV) forms a complex with RNA-directed RNA polymerase 2 (RDR2) to produce double-stranded RNA (dsRNA) precursors essential for plant gene silencing. In the "backtracking-triggered RNA channeling" model, Pol IV backtracks and delivers its transcript's 3' terminus to RDR2, which synthesizes dsRNA. However, the mechanisms underlying Pol IV backtracking and RNA protection from cleavage are unclear. Here, we determined cryo-electron microscopy structures of Pol IV elongation complexes at four states of its nucleotide addition cycle (NAC): posttranslocation, guanosine triphosphate-bound, pretranslocation, and backtracked states. The structures reveal that Pol IV maintains an open DNA cleft and kinked bridge helix in all NAC states, loosely interacts with the nucleoside triphosphate substrate, and barely contacts proximal backtracked nucleotides. Biochemical data indicate that Pol IV is inefficient in forward translocation and RNA cleavage. These findings suggest that Pol IV transcription elongation is prone to backtracking and incapable of RNA hydrolysis, ensuring efficient dsRNA production by Pol IV-RDR2.