Investigations on Dynamic Regulation of Genomic Imprinting in the Arabidopsis Endosperm

Abstract

The rapidly growing world population challenges crop agriculture to maintain a sufficient food supply. The understanding of the regulation of genes responsible for modulating favorable traits, such as seed size, could significantly enhance crop development. The endosperm of flowering plants is the main source of nutrient in the worldwide food chain, including maize and wheat. It consists of two maternal and one paternal allele and therefore, tight control of gene regulation is required to maintain a balanced parental expression. Because of its triploid nature, the endosperm is the main site of genomic imprinting, an epigenetic phenomenon allowing parent-of-origin specific expression of alleles. In this PhD project, van Ekelenburg investigated the regulation of genomic imprinting. The imprinting pattern of a known imprinted gene was shown not to be conserved in hybrids of different species. Furthermore, the gene harboring the causative mutation for the capulet2 mutant was identified and found to be a maternally expressed imprinted gene. Finally, genomic imprinting was found to be dynamically regulated in time and space. Altogether, these results show that imprinting is more dynamic and complex in its regulation than previously thought.