Poster abstracts
Poster number 7 submitted by Natalie Deans
RMR12 is a CHD3 nucleosome remodeler required for maintaining paramutations and normal development
Natalie Deans (Department of Molecular Genetics, The Ohio State University, Columbus, OH), Brian Giacopelli (Department of Molecular Genetics, The Ohio State University, Columbus, OH), Daniel Hlavaty, Emily McCormic (Department of Molecular Genetics, The Ohio State University, Columbus, OH), Charles Addo-Quaye (2Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN), Brian Dilkes (Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN), Jay Hollick (Department of Molecular Genetics, Center for Applied Plant Sciences and Center for RNA Biology, The Ohio State University, Columbus, OH)
Abstract:
In maize, paramutations result in meiotically heritable changes in the regulation of certain alleles of purple plant1 1, a gene encoding a transcription factor required for anthocyanin production2. A strongly expressed Pl1-Rhoades allele is suppressed in trans when combined with a transcriptionally and post-transcriptionally repressed Pl1-Rhoades allele, and both alleles are transmitted in a repressed (denoted Pl´ ) state. At least sixteen loci whose functions are required to maintain repression (rmr) of Pl´ have been identified by ethyl methanesulfonate mutagenesis3. All known RMR proteins mediate 24 nucleotide (24nt) RNA biogenesis4, 5, 6, 7, 8, and four are putative orthologs of Arabidopsis proteins central to an RNA-directed DNA Methylation (RdDM) pathway facilitating repressive chromatin modifications. Here we describe four recessive alleles defining the rmr12 locus. Unlike other rmr-type mutations found to date4, 5, 7, 8, 9, 10, rmr12 mutants display a unique set of defects, including male gametophyte dysfunction, that highlight a novel mechanistic connection between paramutation and developmental gene control. We used positional cloning to discover that rmr12 encodes a Chromodomain Helicase-DNA Binding3 (CHD3) protein whose presumed Arabidopsis ortholog, PICKLE, alters nucleosome positions in vitro11 and affects both development and chromatin modifications specified by RdDM12, 13. Maize CHD3 represents the first RMR protein not having a predicted role in 24nt RNA biogenesis and thus might facilitate paramutations by converting 24nt RNA effectors into meiotically-heritable nucleosome alterations.
References:
1. Hollick et al. 1995 Genetics 141, 709. | 2. Cone et al. 1993 Plant Cell 5, 1795 | 3. Hollick and Chandler 2001 Genetics 157, 369 | 4. Erhard et al. 2009 Science 323, 1201 | 5. Hale et al. 2007 PLoS Biol. 5, 2156 | 6. Nobuta et al. 2008 PNAS 105, 14958 | 7. Stonaker et al. 2009 PLoS Genet. 5, e1000706. | 8. Barbour et al. 2012 Plant Cell 24, 1761 | 9. Dorweiler et al. 2000 Plant Cell 12, 2101. | 10. Parkinson et al. 2007 Dev. Biol. 308, 462. | 11. Ho et al. 2013 Biochim. Biophys. Acta 1829, 199 | 12. Ogas et al. 1997 Science 277, 91 | 13. Yang et al. 2017 Genome Biol. 18, 103
Keywords: Development, Gene regulation, Chromatin