Plant Science Innovation, Center for

 

Document Type

Article

Date of this Version

2015

Citation

Curr Genomics. 16(1): 23-31.

Comments

Copyright © 2015 Bentham Science Publishers. Used by permission.

Abstract

DNA cytosine methylationis an important epigenetic process that is correlated with transgene silencing, transposon suppression, and gene imprinting. In plants, small interfering RNAs (siRNAs) can trigger DNA methylation at loci containing their homolog sequences through a process called RNAdirected DNA methylation (RdDM). In canonical RdDM, 24 nucleotide (nt) siRNAs (ra-siRNAs) will be loaded into their effector protein called ARGONAUTE 4 (AGO4) and subsequently targeted to RdDM loci through base-pairing with the non-coding transcripts produced by DNA-directed RNA Polymerase V. Then, the AGO4-ra-siRNA will recruit the DNA methyltransferase to catalyze de novo DNA methylation. Recent studies also identified non-canonical RdDM pathways that involve microRNAs or 21 nt siRNAs. These RdDM pathways are biologically important since they control responses biotic and abiotic stresses, maintain genome stability and regulate development. Here, we summarize recent pro-gresses of mechanisms governing canonical and non-canonical RdDM pathways.

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