| 词条 | RNA polymerase IV |
| 释义 |
Polymerase IV is specific to plants genomes and is required for the synthesis of over 90% of 24-nt heterochromatic siRNA. [3] FunctionRNA polymerase silences the transposons and repetitive DNA in the siRNA pathway.[1] The siRNA plays a major role in defending the genome against the invading viruses and transposable elements by RNA directed DNA methylation. [3] Polymerase IV and ROS1 demethylase unlocks and recondenses the 5S rDNA chromatin, which is present in seed and used for the development of adult features in plants. [4] Polymerase IV is involved in setting the methylation patterns in the 5S genes during plant maturation.[4] In arabidopsis, polymerase IV is known to interact with an RNA-dependent RNA polymerase, RDR2 and the collective activity of Pol IV-RDR2 is thought to give rise to the short dsRNAs which can be diced in to 24 nt siRNAs by DCL3.[1] [5] References1. ^1 2 {{cite journal | vauthors = Herr AJ, Jensen MB, Dalmay T, Baulcombe DC | title = RNA polymerase IV directs silencing of endogenous DNA | journal = Science | volume = 308 | issue = 5718 | pages = 118–20 | date = April 2005 | pmid = 15692015 | doi = 10.1126/science.1106910 }} {{Polymerases}}2. ^{{cite journal | vauthors = Onodera Y, Haag JR, Ream T, Costa Nunes P, Pontes O, Pikaard CS | title = Plant nuclear RNA polymerase IV mediates siRNA and DNA methylation-dependent heterochromatin formation | journal = Cell | volume = 120 | issue = 5 | pages = 613–22 | date = March 2005 | pmid = 15766525 | doi = 10.1016/j.cell.2005.02.007 }} 3. ^1 {{cite journal | vauthors = Zhang X, Henderson IR, Lu C, Green PJ, Jacobsen SE | title = Role of RNA polymerase IV in plant small RNA metabolism | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 104 | issue = 11 | pages = 4536–41 | date = March 2007 | pmid = 17360559 | pmc = 1810338 | doi = 10.1073/pnas.0611456104 }} 4. ^1 {{cite journal | vauthors = Douet J, Blanchard B, Cuvillier C, Tourmente S | title = Interplay of RNA Pol IV and ROS1 during post-embryonic 5S rDNA chromatin remodeling | journal = Plant & Cell Physiology | volume = 49 | issue = 12 | pages = 1783–91 | date = December 2008 | pmid = 18845569 | doi = 10.1093/pcp/pcn152 }} 5. ^{{cite journal | vauthors = Haag JR, Ream TS, Marasco M, Nicora CD, Norbeck AD, Pasa-Tolic L, Pikaard CS | title = In vitro transcription activities of Pol IV, Pol V, and RDR2 reveal coupling of Pol IV and RDR2 for dsRNA synthesis in plant RNA silencing | journal = Molecular Cell | volume = 48 | issue = 5 | pages = 811–8 | date = December 2012 | pmid = 23142082 | pmc = 3532817 | doi = 10.1016/j.molcel.2012.09.027 }} 1 : Enzymes |
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