Respective contributions of Arabidopsis DCL2 and DCL4 to RNA silencing

Parent, J. S., Bouteiller, N., Elmayan, T., Vaucheret, H. (January 2015) Respective contributions of Arabidopsis DCL2 and DCL4 to RNA silencing. Plant Journal, 81 (2). pp. 223-232. ISSN 09607412

URL: http://www.ncbi.nlm.nih.gov/pubmed/25376953
DOI: 10.1111/tpj.12720

Abstract

Dicer proteins are central to the different mechanisms involving RNA interference. Plants have evolved multiple DICER-LIKE (DCL) copies, thus enabling functional diversification. In Arabidopsis, DCL2 and DCL4 process double-stranded RNA into 22 and 21 nucleotide small interfering (si)RNAs, respectively, and have overlapping functions with regards to virus and transgene silencing. Nonetheless, some studies have reported that dcl2 or dcl4 single mutations are sometimes sufficient to hinder silencing. To better dissect the role of DCL2 and DCL4, we analyzed silencing kinetics and efficiencies using different transgenic systems in single and double mutant backgrounds. The results indicate that DCL2 stimulates transitivity and secondary siRNA production through DCL4 while being sufficient for silencing on its own. Notably, silencing of 35S-driven transgenes functions more efficiently in dcl4 mutants, indicating that DCL4 mostly obscures DCL2 in wild-type plants. Nonetheless, in a dcl4 mutant compromised in phloem-originating silencing, ectopically expressed DCL2 allows restoration of silencing, suggesting that DCL2 is not, or poorly, expressed in phloem. Remarkably, this ectopic DCL2 contribution to phloem-originating silencing is dependent on the activity of RNA-DEPENDENT RNA POLYMERASE6. These results indicate that, despite differences in the silencing activity of their small RNA products, DCL2 and DCL4 mostly act redundantly yet hierarchically when present simultaneously.

Item Type: Paper
Uncontrolled Keywords: Arabidopsis thaliana DICER-LIKE proteins plant genetics RNA interference small RNA transgene silencing
Subjects: organism description > plant > Arabidopsis
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification
bioinformatics > genomics and proteomics > genetics & nucleic acid processing
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > RNA silencing
CSHL Authors:
Communities: CSHL labs > Martienssen lab
Depositing User: Matt Covey
Date: 1 January 2015
Date Deposited: 22 Jan 2015 19:38
Last Modified: 22 Jan 2015 19:38
Related URLs:
URI: http://repository.cshl.edu/id/eprint/31139

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