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Structure and mechanism of the plant RNA polymerase V.

ABSTRACT: In addition to the conserved RNA polymerases I to III (Pols I to III) in eukaryotes, two atypical polymerases, Pols IV and V, specifically produce noncoding RNA in the RNA-directed DNA methylation pathway in plants. Here, we report on the structures of cauliflower Pol V in the free and elongation conformations. A conserved tyrosine residue of NRPE2 stacks with a double-stranded DNA branch of the transcription bubble to potentially attenuate elongation by inducing transcription stalling. The nontemplate DNA strand is captured by NRPE2 to enhance backtracking, thereby increasing 3'-5' cleavage, which likely underpins Pol V's high fidelity. The structures also illuminate the mechanism of Pol V transcription stalling and enhanced backtracking, which may be important for Pol V's retention on chromatin to serve its function in tethering downstream factors for RNA-directed DNA methylation.

SUBMITTER: Xie G

PROVIDER: S-EPMC10041816 | biostudies-literature | 2023 Mar

REPOSITORIES: biostudies-literature

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Structure and mechanism of the plant RNA polymerase V.

Xie Guohui G Du Xuan X Hu Hongmiao H Li Sisi S Cao Xiaofeng X Jacobsen Steven E SE Du Jiamu J

Science (New York, N.Y.) 20230309 6638

In addition to the conserved RNA polymerases I to III (Pols I to III) in eukaryotes, two atypical polymerases, Pols IV and V, specifically produce noncoding RNA in the RNA-directed DNA methylation pathway in plants. Here, we report on the structures of cauliflower Pol V in the free and elongation conformations. A conserved tyrosine residue of NRPE2 stacks with a double-stranded DNA branch of the transcription bubble to potentially attenuate elongation by inducing transcription stalling. The nont ...[more]

PMID: 36893216

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