The RNA Export Factor ALY1 Enables Genome-Wide RNA-Directed DNA Methylation.

RNA-directed DNA methylation (RdDM) is a set of mechanisms by which transcriptionally repressive DNA and histone methylation are targeted to viruses, transposable elements, and some transgenes. We identified an Arabidopsis () mutant in which all forms of RdDM are deficient, leading to transcriptional activation of some transposable elements and the inability to initiate transgene silencing. The corresponding gene, , encodes an RNA binding nuclear export protein.