MATERNAL CONTROL OF EMBRYOGENESIS BY MEDEA, A POLYCOMB GROUP GENE IN ARABIDOPSIS

The gametophytic maternal effect mutant medea (mea) shows aberrant gro wth regulation during embryogenesis in Arabidopsis thaliana. Embryos d erived from mea eggs grow excessively and die during seed desiccation. Embryo lethality is independent of the paternal contribution and gene dosage. The mea phenotype is consistent with the parental conflict th eory for the evolution of parent-of-origin-specific effects. MEA encod es a SET domain protein similar to Enhancer of zeste, a member of the Polycomb group. In animals, Polycomb group proteins ensure the stable inheritance of expression patterns through cell division and regulate the control of cell proliferation.