Non-canonical RNA-directed DNA methylation

A Corrigendum to this article was published on 12 December 2016


Small RNA-directed DNA methylation (RdDM) has been extensively studied in plants, resulting in a deep understanding of a major ‘canonical RdDM’ mechanism. However, current models of canonical RdDM cannot explain how this self-perpetuating mechanism is initiated. Recent investigations into the initiation of epigenetic silencing have determined that there are several alternative ‘non-canonical RdDM’ pathways that function through distinct mechanisms to modify chromatin. This Review aims to illustrate the diversity of non-canonical RdDM mechanisms described to date, recognize common themes within this dizzying array of interconnected pathways, and identify the key unanswered questions remaining in this field.

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Figure 1: The canonical RdDM pathway.
Figure 2: PTGS in plants.
Figure 3: Pol II transcripts target DNA methylation through the non-canonical RdDM pathways.
Figure 4: Less understood mechanisms of non-canonical RdDM.


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D.C.-G. is supported by a Nuevo Leon state fellowship from the Mexico National Council of Science and Technology. The Slotkin lab is supported by U.S. National Science Foundation grants MCB-1252370 and MCB-1608392.

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Correspondence to R. Keith Slotkin.

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Cuerda-Gil, D., Slotkin, R. Non-canonical RNA-directed DNA methylation. Nature Plants 2, 16163 (2016).

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