| Structural highlights
Function
NRPD1_ARATH DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates (By similarity). Largest and catalytic component of RNA polymerase IV which mediates 24-nt short-interfering RNAs (siRNA) accumulation. Implicated in siRNA-directed heterochromatin formation through the action of DCL3 and AGO4, and subsequent DNA methylation-dependent silencing of targeted sequences. Essential component of a self-reinforcing loop coupling de novo DNA methylation to siRNA production. Required for intercellular but not intracellular RNA interference (RNAi) leading to systemic post-transcriptional gene silencing. Involved in the maintenance of post-transcriptional RNA silencing.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16]
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[17]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
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- ↑ Hamilton A, Voinnet O, Chappell L, Baulcombe D. Two classes of short interfering RNA in RNA silencing. EMBO J. 2002 Sep 2;21(17):4671-9. PMID:12198169 doi:10.1093/emboj/cdf464
- ↑ Herr AJ, Jensen MB, Dalmay T, Baulcombe DC. RNA polymerase IV directs silencing of endogenous DNA. Science. 2005 Apr 1;308(5718):118-20. doi: 10.1126/science.1106910. Epub 2005 Feb, 3. PMID:15692015 doi:https://dx.doi.org/10.1126/science.1106910
- ↑ Onodera Y, Haag JR, Ream T, Costa Nunes P, Pontes O, Pikaard CS. Plant nuclear RNA polymerase IV mediates siRNA and DNA methylation-dependent heterochromatin formation. Cell. 2005 Mar 11;120(5):613-22. PMID:15766525 doi:10.1016/j.cell.2005.02.007
- ↑ Pontier D, Yahubyan G, Vega D, Bulski A, Saez-Vasquez J, Hakimi MA, Lerbs-Mache S, Colot V, Lagrange T. Reinforcement of silencing at transposons and highly repeated sequences requires the concerted action of two distinct RNA polymerases IV in Arabidopsis. Genes Dev. 2005 Sep 1;19(17):2030-40. PMID:16140984 doi:10.1101/gad.348405
- ↑ Dunoyer P, Himber C, Voinnet O. DICER-LIKE 4 is required for RNA interference and produces the 21-nucleotide small interfering RNA component of the plant cell-to-cell silencing signal. Nat Genet. 2005 Dec;37(12):1356-60. Epub 2005 Nov 6. PMID:16273107 doi:https://dx.doi.org/10.1038/ng1675
- ↑ Borsani O, Zhu J, Verslues PE, Sunkar R, Zhu JK. Endogenous siRNAs derived from a pair of natural cis-antisense transcripts regulate salt tolerance in Arabidopsis. Cell. 2005 Dec 29;123(7):1279-91. PMID:16377568 doi:10.1016/j.cell.2005.11.035
- ↑ Pontes O, Li CF, Costa Nunes P, Haag J, Ream T, Vitins A, Jacobsen SE, Pikaard CS. The Arabidopsis chromatin-modifying nuclear siRNA pathway involves a nucleolar RNA processing center. Cell. 2006 Jul 14;126(1):79-92. PMID:16839878 doi:10.1016/j.cell.2006.05.031
- ↑ Zhang X, Henderson IR, Lu C, Green PJ, Jacobsen SE. Role of RNA polymerase IV in plant small RNA metabolism. Proc Natl Acad Sci U S A. 2007 Mar 13;104(11):4536-41. PMID:17360559 doi:10.1073/pnas.0611456104
- ↑ Smith LM, Pontes O, Searle I, Yelina N, Yousafzai FK, Herr AJ, Pikaard CS, Baulcombe DC. An SNF2 protein associated with nuclear RNA silencing and the spread of a silencing signal between cells in Arabidopsis. Plant Cell. 2007 May;19(5):1507-21. doi: 10.1105/tpc.107.051540. Epub 2007 May, 25. PMID:17526749 doi:https://dx.doi.org/10.1105/tpc.107.051540
- ↑ Dunoyer P, Himber C, Ruiz-Ferrer V, Alioua A, Voinnet O. Intra components of the microRNA and heterochromatic silencing pathways. Nat Genet. 2007 Jul;39(7):848-56. PMID:17558406 doi:10.1038/ng2081
- ↑ Brosnan CA, Mitter N, Christie M, Smith NA, Waterhouse PM, Carroll BJ. Nuclear gene silencing directs reception of long-distance mRNA silencing in Arabidopsis. Proc Natl Acad Sci U S A. 2007 Sep 11;104(37):14741-6. doi:, 10.1073/pnas.0706701104. Epub 2007 Sep 4. PMID:17785412 doi:https://dx.doi.org/10.1073/pnas.0706701104
- ↑ Mosher RA, Schwach F, Studholme D, Baulcombe DC. PolIVb influences RNA-directed DNA methylation independently of its role in siRNA biogenesis. Proc Natl Acad Sci U S A. 2008 Feb 26;105(8):3145-50. PMID:18287047 doi:10.1073/pnas.0709632105
- ↑ Eamens A, Vaistij FE, Jones L. NRPD1a and NRPD1b are required to maintain post-transcriptional RNA silencing and RNA-directed DNA methylation in Arabidopsis. Plant J. 2008 Aug;55(4):596-606. PMID:18433438 doi:10.1111/j.1365-313X.2008.03525.x
- ↑ Pérez-Hormaeche J, Potet F, Beauclair L, Le Masson I, Courtial B, Bouché N, Lucas H. Invasion of the Arabidopsis genome by the tobacco retrotransposon Tnt1 is controlled by reversible transcriptional gene silencing. Plant Physiol. 2008 Jul;147(3):1264-78. PMID:18467467 doi:10.1104/pp.108.117846
- ↑ 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
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