DNA methylation and epigenetic inheritance during plant gametogenesis
- First Online:
- 459 Downloads
In plants, newly acquired epigenetic states of transcriptional gene activity are readily transmitted to the progeny. This is in contrast to mammals, where only rare cases of transgenerational inheritance of new epigenetic traits have been reported (FASEB J 12:949–957, 1998; Nat Genet 23:314–318, 1999; Proc Natl Acad Sci U S A 100:2538–2543, 2003). Epigenetic inheritance in plants seems to rely on cytosine methylation maintained through meiosis and postmeiotic mitoses, giving rise to gametophytes. In particular, maintenance of CpG methylation (mCpG) appears to play a central role, guiding the distribution of other epigenetic signals such as histone H3 methylation and non-CpG DNA methylation. The evolutionarily conserved DNA methyltransferase MET1 is responsible for copying mCpG patterns through DNA replication in the gametophytic phase. The importance of gametophytic MET1 activity is illustrated by the phenotypes of met1 mutants that are severely compromised in the accuracy of epigenetic inheritance during gametogenesis. This includes elimination of imprinting at paternally silent loci such as FWA or MEDEA (MEA). The importance of DNA methylation in gametophytic imprinting has been reinforced by the discovery of DEMETER (DME), encoding putative DNA glycosylase involved in the removal of mC. DME opposes transcriptional silencing associated with imprinting activities of the MEA/FIE polycomb group complex.
- Lindroth AM, Shultis D, Jasencakova Z, Fuchs J, Johnson L, Schubert D, Patnaik D, Pradhan S, Goodrich J, Schubert I, Jenuwein T, Khorasanizadeh S, Jacobsen SE (2004) Dual histone H3 methylation marks at lysines 9 and 27 required for interaction with CHROMOMETHYLASE3. EMBO J 23:4286–4296PubMedCrossRefGoogle Scholar
- Rocha PS, Sheikh M, Melchiorre R, Fagard M, Boutet S, Loach R, Moffatt B, Wagner C, Vaucheret H, Furner I (2005) The Arabidopsis HOMOLOGY-DEPENDENT GENE SILENCING1 gene codes for an S-adenosyl-l-homocysteine hydrolase required for DNA methylation-dependent gene silencing. Plant Cell 17:404–417PubMedCrossRefGoogle Scholar
- Saze H (2003) Maintenance of CpG methylation is essential for epigenetic inheritance during plant gametogenesis. PhD thesis, Friedrich Miescher Institute, Basel, SwitzerlandGoogle Scholar