| Structural highlights
Function
[AGO1_ARATH] Involved in RNA-mediated post-transcriptional gene silencing (PTGS). Main component of the RNA-induced silencing complex (RISC) that binds to a short guide RNA such as microRNA (miRNA) or small interfering RNA (siRNA). RISC uses the mature miRNA or siRNA as a guide for slicer-directed cleavage of homologous mRNAs to repress gene expression. Requires DRB1 for directional loading of the small RNA duplex (guide stand and passenger strand) onto RISC for passenger strand degradation. Unlike animal RISC that associates in high molecular weight complex, Arabidopsis RISC is probably composed only of the AGO1 protein and associated RNA without any other proteins. Associates mainly with miRNAs of 21 nucleotide in length and preferentially recruits small RNAs with a 5' terminal uridine. Associates with 22 nucleotide miRNAs to trigger RDR6-dependent secondary siRNAs biogenesis. This pathway amplifies silencing by using the target RNA as substrate to generate secondary siRNAs. Binds to miR168 which targets its own mRNA for repression, establishing a homeostatic regulatory loop. Involved in antiviral RNA silencing by contributing to viral RNA clearance. Is capable of targeting viral RNAs with more compact structures than AGO7 which favors less structured RNA targets. May not associate with 24 nucleotide siRNAs involved in chromatin silencing. Essential for multiple processes in development. Essential for proper development of leaves and floral organs, and formation of axillary meristems. Like AGO10, required for stem cell function and organ polarity.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]
Publication Abstract from PubMed
The RISC-associated Argonaute (Ago) proteins play the catalytic role for RISC-mediated gene regulation by selecting small RNAs and subsequent targeting and cleavage of complementary mRNAs. Ago Mid domains are proposed to play essential roles in small RNA sorting. Here, we report the crystal structures of Arabidopsis Ago1 Mid domain and its chimera mutant with part of Ago1 replaced by Ago4. The structures demonstrate that a single amino insertion in the nucleotide specificity loop of AtAgo1 will change the nucleotide binding preference of AtAgo1 from "5'-U" to "5'-A". Moreover, we identify a long positively charged groove located along the "5'-end-nucleotide specificity loop" and occupied by several sulfate ions with the distance of 9-11A distance, indicating a putative mRNA target binding groove.
Structural insights into small RNA sorting and mRNA target binding by Arabidopsis Argonaute Mid domains.,Zha X, Xia Q, Adam Yuan Y FEBS Lett. 2012 Sep 21;586(19):3200-7. doi: 10.1016/j.febslet.2012.06.038. Epub, 2012 Jul 3. PMID:22771475[12]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Bohmert K, Camus I, Bellini C, Bouchez D, Caboche M, Benning C. AGO1 defines a novel locus of Arabidopsis controlling leaf development. EMBO J. 1998 Jan 2;17(1):170-80. PMID:9427751 doi:http://dx.doi.org/10.1093/emboj/17.1.170
- ↑ Kidner CA, Martienssen RA. The role of ARGONAUTE1 (AGO1) in meristem formation and identity. Dev Biol. 2005 Apr 15;280(2):504-17. PMID:15882589 doi:http://dx.doi.org/10.1016/j.ydbio.2005.01.031
- ↑ Baumberger N, Baulcombe DC. Arabidopsis ARGONAUTE1 is an RNA Slicer that selectively recruits microRNAs and short interfering RNAs. Proc Natl Acad Sci U S A. 2005 Aug 16;102(33):11928-33. Epub 2005 Aug 4. PMID:16081530 doi:http://dx.doi.org/10.1073/pnas.0505461102
- ↑ Zhang X, Yuan YR, Pei Y, Lin SS, Tuschl T, Patel DJ, Chua NH. Cucumber mosaic virus-encoded 2b suppressor inhibits Arabidopsis Argonaute1 cleavage activity to counter plant defense. Genes Dev. 2006 Dec 1;20(23):3255-68. PMID:17158744 doi:http://dx.doi.org/20/23/3255
- ↑ Mi S, Cai T, Hu Y, Chen Y, Hodges E, Ni F, Wu L, Li S, Zhou H, Long C, Chen S, Hannon GJ, Qi Y. Sorting of small RNAs into Arabidopsis argonaute complexes is directed by the 5' terminal nucleotide. Cell. 2008 Apr 4;133(1):116-27. doi: 10.1016/j.cell.2008.02.034. Epub 2008 Mar, 13. PMID:18342361 doi:http://dx.doi.org/10.1016/j.cell.2008.02.034
- ↑ Montgomery TA, Howell MD, Cuperus JT, Li D, Hansen JE, Alexander AL, Chapman EJ, Fahlgren N, Allen E, Carrington JC. Specificity of ARGONAUTE7-miR390 interaction and dual functionality in TAS3 trans-acting siRNA formation. Cell. 2008 Apr 4;133(1):128-41. doi: 10.1016/j.cell.2008.02.033. Epub 2008 Mar, 13. PMID:18342362 doi:http://dx.doi.org/10.1016/j.cell.2008.02.033
- ↑ Takeda A, Iwasaki S, Watanabe T, Utsumi M, Watanabe Y. The mechanism selecting the guide strand from small RNA duplexes is different among argonaute proteins. Plant Cell Physiol. 2008 Apr;49(4):493-500. doi: 10.1093/pcp/pcn043. Epub 2008, Mar 14. PMID:18344228 doi:http://dx.doi.org/10.1093/pcp/pcn043
- ↑ Qu F, Ye X, Morris TJ. Arabidopsis DRB4, AGO1, AGO7, and RDR6 participate in a DCL4-initiated antiviral RNA silencing pathway negatively regulated by DCL1. Proc Natl Acad Sci U S A. 2008 Sep 23;105(38):14732-7. doi:, 10.1073/pnas.0805760105. Epub 2008 Sep 17. PMID:18799732 doi:http://dx.doi.org/10.1073/pnas.0805760105
- ↑ Cuperus JT, Carbonell A, Fahlgren N, Garcia-Ruiz H, Burke RT, Takeda A, Sullivan CM, Gilbert SD, Montgomery TA, Carrington JC. Unique functionality of 22-nt miRNAs in triggering RDR6-dependent siRNA biogenesis from target transcripts in Arabidopsis. Nat Struct Mol Biol. 2010 Aug;17(8):997-1003. doi: 10.1038/nsmb.1866. Epub 2010, Jun 18. PMID:20562854 doi:http://dx.doi.org/10.1038/nsmb.1866
- ↑ Mallory AC, Hinze A, Tucker MR, Bouche N, Gasciolli V, Elmayan T, Lauressergues D, Jauvion V, Vaucheret H, Laux T. Redundant and specific roles of the ARGONAUTE proteins AGO1 and ZLL in development and small RNA-directed gene silencing. PLoS Genet. 2009 Sep;5(9):e1000646. doi: 10.1371/journal.pgen.1000646. Epub 2009 , Sep 18. PMID:19763164 doi:http://dx.doi.org/10.1371/journal.pgen.1000646
- ↑ Eamens AL, Smith NA, Curtin SJ, Wang MB, Waterhouse PM. The Arabidopsis thaliana double-stranded RNA binding protein DRB1 directs guide strand selection from microRNA duplexes. RNA. 2009 Dec;15(12):2219-35. doi: 10.1261/rna.1646909. Epub 2009 Oct 27. PMID:19861421 doi:http://dx.doi.org/10.1261/rna.1646909
- ↑ Zha X, Xia Q, Adam Yuan Y. Structural insights into small RNA sorting and mRNA target binding by Arabidopsis Argonaute Mid domains. FEBS Lett. 2012 Sep 21;586(19):3200-7. doi: 10.1016/j.febslet.2012.06.038. Epub, 2012 Jul 3. PMID:22771475 doi:http://dx.doi.org/10.1016/j.febslet.2012.06.038
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