7eu1

The cryo-EM structure of A. thaliana Pol IV-RDR2 holoenzymeThe cryo-EM structure of A. thaliana Pol IV-RDR2 holoenzyme

Structural highlights

7eu1 is a 10 chain structure with sequence from Arabidopsis thaliana. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 3.86Å
Ligands:	,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

NRPBC_ARATH DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Component of RNA polymerase II which synthesizes mRNA precursors and many functional non-coding RNAs. Pol II is the central component of the basal RNA polymerase II transcription machinery. It is composed of mobile elements that move relative to each other. Component of RNA polymerases IV and V which mediate short-interfering RNAs (siRNA) accumulation and subsequent RNA-directed DNA methylation-dependent (RdDM) transcriptional gene silencing (TGS) of endogenous repeated sequences, including transposable elements.^[1]

Publication Abstract from PubMed

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.

Pol IV and RDR2: A two-RNA-polymerase machine that produces double-stranded RNA.,Huang K, Wu XX, Fang CL, Xu ZG, Zhang HW, Gao J, Zhou CM, You LL, Gu ZX, Mu WH, Feng Y, Wang JW, Zhang Y Science. 2021 Dec 24;374(6575):1579-1586. doi: 10.1126/science.abj9184. Epub 2021 , Dec 23. PMID:34941388^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Ream TS, Haag JR, Wierzbicki AT, Nicora CD, Norbeck AD, Zhu JK, Hagen G, Guilfoyle TJ, Pasa-Tolić L, Pikaard CS. Subunit compositions of the RNA-silencing enzymes Pol IV and Pol V reveal their origins as specialized forms of RNA polymerase II. Mol Cell. 2009 Jan 30;33(2):192-203. PMID:19110459 doi:10.1016/j.molcel.2008.12.015
↑ Huang K, Wu XX, Fang CL, Xu ZG, Zhang HW, Gao J, Zhou CM, You LL, Gu ZX, Mu WH, Feng Y, Wang JW, Zhang Y. Pol IV and RDR2: A two-RNA-polymerase machine that produces double-stranded RNA. Science. 2021 Dec 24;374(6575):1579-1586. PMID:34941388 doi:10.1126/science.abj9184

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

[1] Ream TS, Haag JR, Wierzbicki AT, Nicora CD, Norbeck AD, Zhu JK, Hagen G, Guilfoyle TJ, Pasa-Tolić L, Pikaard CS. Subunit compositions of the RNA-silencing enzymes Pol IV and Pol V reveal their origins as specialized forms of RNA polymerase II. Mol Cell. 2009 Jan 30;33(2):192-203. PMID:19110459 doi:10.1016/j.molcel.2008.12.015

[2] Huang K, Wu XX, Fang CL, Xu ZG, Zhang HW, Gao J, Zhou CM, You LL, Gu ZX, Mu WH, Feng Y, Wang JW, Zhang Y. Pol IV and RDR2: A two-RNA-polymerase machine that produces double-stranded RNA. Science. 2021 Dec 24;374(6575):1579-1586. PMID:34941388 doi:10.1126/science.abj9184

[1]

[2]