TY - JOUR
T1 - Ovule siRNAs methylate protein-coding genes in trans
AU - Burgess, Diane
AU - Chow, Hiu Tung
AU - Grover, Jeffrey W.
AU - Freeling, Michael
AU - Mosher, Rebecca A.
N1 - Funding Information: We are grateful to Dr Eric Lyons and the CoGe team for development and maintenance of CoGe. We thank Dr. Damon Lisch for critical reading of an earlier draft and for suggesting that we look for transmethylation. The authors are grateful for support from the National Science Foundation (IOS-1546825 to R.A.M. and M.F.) and the USDA National Institute of Food and Agriculture (AFRI 2021-67013-33797 to R.A.M. and AFRI 2014-67013-21661, subaward C0471A-B to M.F.). Publisher Copyright: © American Society of Plant Biologists 2022. All rights reserved.
PY - 2022/10
Y1 - 2022/10
N2 - Twenty-four-nucleotide (nt) small interfering RNAs (siRNAs) maintain asymmetric DNA methylation at thousands of euchromatic transposable elements in plant genomes in a process called RNA-directed DNA methylation (RdDM). RdDM is dispensable for growth and development in Arabidopsis thaliana, but is required for reproduction in other plants, such as Brassica rapa. The 24-nt siRNAs are abundant in maternal reproductive tissue, due largely to overwhelming expression from a few loci in the ovule and developing seed coat, termed siren loci. A recent study showed that 24-nt siRNAs produced in the anther tapetal tissue can methylate male meiocyte genes in trans. Here we show that in B. rapa, a similar process takes place in female tissue. siRNAs are produced from gene fragments embedded in some siren loci, and these siRNAs can trigger methylation in trans at related protein-coding genes. This trans-methylation is associated with silencing of some target genes and may be responsible for seed abortion in RdDM mutants. Furthermore, we demonstrate that a consensus sequence in at least two families of DNA transposons is associated with abundant siren expression, most likely through recruitment of CLASSY3, a putative chromatin remodeler. This research describes a mechanism whereby RdDM influences gene expression and sheds light on the role of RdDM during plant reproduction.
AB - Twenty-four-nucleotide (nt) small interfering RNAs (siRNAs) maintain asymmetric DNA methylation at thousands of euchromatic transposable elements in plant genomes in a process called RNA-directed DNA methylation (RdDM). RdDM is dispensable for growth and development in Arabidopsis thaliana, but is required for reproduction in other plants, such as Brassica rapa. The 24-nt siRNAs are abundant in maternal reproductive tissue, due largely to overwhelming expression from a few loci in the ovule and developing seed coat, termed siren loci. A recent study showed that 24-nt siRNAs produced in the anther tapetal tissue can methylate male meiocyte genes in trans. Here we show that in B. rapa, a similar process takes place in female tissue. siRNAs are produced from gene fragments embedded in some siren loci, and these siRNAs can trigger methylation in trans at related protein-coding genes. This trans-methylation is associated with silencing of some target genes and may be responsible for seed abortion in RdDM mutants. Furthermore, we demonstrate that a consensus sequence in at least two families of DNA transposons is associated with abundant siren expression, most likely through recruitment of CLASSY3, a putative chromatin remodeler. This research describes a mechanism whereby RdDM influences gene expression and sheds light on the role of RdDM during plant reproduction.
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U2 - 10.1093/plcell/koac197
DO - 10.1093/plcell/koac197
M3 - Article
C2 - 35781738
SN - 1040-4651
VL - 34
SP - 3647
EP - 3664
JO - Plant Cell
JF - Plant Cell
IS - 10
ER -