Abstract
Epigenetic states can enrich the transcriptional repertoire of a chromatin template, by enabling responses other than simply ON or OFF, like, for example fast, cell-specific, quantitative, parent of origin, transgenerational, etc.
The Arabidopsis thaliana FWA gene displays parent of origin gene expression during the reproductive phase and it is a model system for imprinting in the endosperm. A pFWA::GFP reporter monitors maternal gene expression in endosperm and lack of activity in both the surrounding maternal tissue and the paternal copy. These transcription states are dictated by DNA methylation status of the two SINE repeats present in the FWA promoter: FWA DNA is permanently methylated, except the maternal methylation of FWA is lost just before fertilization in an active process mediated by the DNA glycosylase DEMETER and only the endosperm inherits an active state.
We aim to identify new components involved in DNA de-methylation by characterizing mutations that impede FWA reporter imprinting, termed alac mutants (Alarm Clock for FWA imprinting). I will focus on one such mutant, alac4, that also affects the imprinting of at least two other genes.
