Abstract |
Chromosome dosage has substantial effects on reproductive isolation and speciation in both plants and animals, but the underlying mechanisms are largely obscure 1 . Transposable elements in animals can regulate hybridity through maternal small RNA 2 , whereas small RNAs in plants have been postulated to regulate dosage response via neighboring imprinted genes3,4. Here we show that a highly conserved microRNA in plants, miR845, targets the tRNAMet primer-binding site (PBS) of long terminal repeat (LTR) retrotransposons in Arabidopsis pollen, and triggers the accumulation of 21-22-nucleotide (nt) small RNAs in a dose-dependent fashion via RNA polymerase IV. We show that these epigenetically activated small interfering RNAs (easiRNAs) mediate hybridization barriers between diploid seed parents and tetraploid pollen parents (the ' triploid block'), and that natural variation for miR845 may account for 'endosperm balance' allowing the formation of triploid seeds. Targeting of the PBS with small RNA is a common mechanism for transposon control in mammals and plants, and provides a uniquely sensitive means to monitor chromosome dosage and imprinting in the developing seed.
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Authors | Filipe Borges, Jean-Sébastien Parent, Frédéric van Ex, Philip Wolff, German Martínez, Claudia Köhler, Robert A Martienssen |
Journal | Nature genetics
(Nat Genet)
Vol. 50
Issue 2
Pg. 186-192
(02 2018)
ISSN: 1546-1718 [Electronic] United States |
PMID | 29335544
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
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Chemical References |
- MIRN845A microRNA, Arabidopsis
- MIRN845B microRNA, Arabidopsis
- MicroRNAs
- RNA, Plant
- Retroelements
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Topics |
- Arabidopsis
(genetics)
- Dosage Compensation, Genetic
(genetics)
- Gene Expression Regulation, Plant
- Genome, Plant
- MicroRNAs
(genetics, physiology)
- Polyploidy
- RNA, Plant
(genetics)
- Retroelements
(physiology)
- Terminal Repeat Sequences
(genetics)
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