Genomic imprinting is not always essential for seed development, a study published online in Nature suggests. The finding may have implications for stem cell research.
Genomic imprinting is a form of gene regulation that starts early in life. It causes certain genes to be expressed from just the maternally inherited DNA, whilst others are expressed only from the paternal DNA. The phenomenon is well known in mammals, but it also occurs in flowering plants.
In a fertilized seed the endosperm provides nutrients to the developing embryo. Arp Schnittger and colleagues created a mutant plant in which the endosperm is derived solely from maternal DNA. They find that, in a certain mutant background that affects chromatin remodelling, the endosperm can develop normally without a paternal contribution, suggesting that genomic imprinting per se is not essential for seed development. Mammalian embryos lacking appropriate imprints die, but the uniparental endosperm seedlings in this study are viable albeit smaller than normal.
Imprinting is a hot topic in stem cell research, because researchers are trying to clone viable, healthy embryos from cells lacking imprints. So the study contributes useful information to this field and also says something about the evolution of endosperm.
Arp Schnittger (University of Cologne, Germany)
Abstract available online.
(C) Nature press release.
Message posted by: Trevor M. D'Souza