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RNA polymerase V targets transcriptional silencing components to promoters of protein‐coding genes
Author(s) -
Zheng Qi,
Rowley M. Jordan,
Böhmdorfer Gudrun,
Sandhu Davinder,
Gregory Brian D.,
Wierzbicki Andrzej T.
Publication year - 2013
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12034
Subject(s) - promoter , rna polymerase ii , gene , gene silencing , biology , genetics , gene expression
Summary Transcriptional gene silencing controls transposons and other repetitive elements through RNA ‐directed DNA methylation ( R d DM ) and heterochromatin formation. A key component of the Arabidopsis R d DM pathway is ARGONAUTE 4 ( AGO 4), which associates with siRNAs to mediate DNA methylation. Here, we show that AGO 4 preferentially targets transposable elements embedded within promoters of protein‐coding genes. This pattern of AGO 4 binding cannot be simply explained by the sequences of AGO 4‐bound si RNA s; instead, AGO 4 binding to specific gene promoters is also mediated by long non‐coding RNA s (lnc RNA s) produced by RNA polymerase V . lnc RNA ‐mediated AGO 4 binding to gene promoters directs asymmetric DNA methylation to these genomic regions and is involved in regulating the expression of targeted genes. Finally, AGO 4 binding overlaps sites of DNA methylation affected by the biotic stress response. Based on these findings, we propose that the targets of AGO 4‐directed R d DM are regulatory units responsible for controlling gene expression under specific environmental conditions.