Abstract
Paternally and maternally inherited chromosomes are not functionally equal in mammals and plants, since certain genes are expressed in a parent-of-origin specific manner. This phenomenon, called genomic imprinting, is controlled by differential epigenetic modifications of histone and DNA methylation on the parental genes.
We have been studying the mechanism of genomic imprinting of FWA in Arabidopsis. The gene displays maternal origin specific expression pattern in the endosperm. The activation of maternal allele requires cytosine demethylation of the tandem repeats at the 5' region of FWA in the central cell, which is the progenitor cell of endosperm before fertilization. By contrast, silent status of the paternal allele is maintained by DNA methyltransferase activity. Recently, we have obtained alac (alarm clock for FWA imprinting) mutants that are defective in activation of FWA-GFP reporter in the central cell. Analysis of these mutants is underway
