7EU0

The cryo-EM structure of A. thaliana Pol IV-RDR2 backtracked complex

Summary for 7EU0

• Entry DOI: 10.2210/pdb7eu0/pdb
• EMDB information: 31305
• Descriptor: DNA-directed RNA polymerase IV subunit 1, DNA-directed RNA polymerases II, IV and V subunit 12, RNA-dependent RNA polymerase 2, ... (17 entities in total)
• Functional Keywords: dna-directed rna polymerase iv, rna- dependent rna polymerase 2, rna-directed dna methylation pathway, transcription
• Biological source: Arabidopsis thaliana (Mouse-ear cress); More
• Total number of polymer chains: 15
• Total formula weight: 596304.15

Authors

Fang, C.L.,Wu, X.X.,Huang, K.,Zhang, Y. (deposition date: 2021-05-15, release date: 2021-12-29, Last modification date: 2024-06-05)

Primary citation

Huang, K.,Wu, X.X.,Fang, C.L.,Xu, Z.G.,Zhang, H.W.,Gao, J.,Zhou, C.M.,You, L.L.,Gu, Z.X.,Mu, W.H.,Feng, Y.,Wang, J.W.,Zhang, Y.
Pol IV and RDR2: A two-RNA-polymerase machine that produces double-stranded RNA.
Science, 374:1579-1586, 2021

PubMed Abstract: DNA methylation affects gene expression and maintains genome integrity. The DNA-dependent RNA polymerase IV (Pol IV), together with the RNA-dependent RNA polymerase RDR2, produces double-stranded small interfering RNA precursors essential for establishing and maintaining DNA methylation in plants. We determined the cryo–electron microscopy structures of the Pol IV–RDR2 holoenzyme and the backtracked transcription elongation complex. These structures reveal that Pol IV and RDR2 form a complex with their active sites connected by an interpolymerase channel, through which the Pol IV–generated transcript is handed over to the RDR2 active site after being backtracked, where it is used as the template for double-stranded RNA (dsRNA) synthesis. Our results describe a ‘backtracking-triggered RNA channeling’ mechanism underlying dsRNA synthesis and also shed light on the evolutionary trajectory of eukaryotic RNA polymerases.

PubMed: 34941388
DOI: 10.1126/science.abj9184

Experimental method

ELECTRON MICROSCOPY (3.16 Å)