title: Genomic imprinting and endosperm development in flowering plants.
abstract: Genomic imprinting, the parent-of-origin-specific expression of genes, plays an important role in the seed development of flowering plants. As different sets of genes are imprinted and hence silenced in maternal and paternal gametophyte genomes, the contributions of the parental genomes to the offspring are not equal. Imbalance between paternally and maternally imprinted genes, for instance as a result of interploidy crosses, or in seeds in which imprinting has been manipulated, results in aberrant seed development. It is predominantly the endosperm, and not or to a far lesser extent the embryo, that is affected by such imbalance. Deviation from the normal 2m:1p ratio in the endosperm genome has a severe effect on endosperm development, and often leads to seed abortion. Molecular expression data for imprinted genes suggest that genomic imprinting takes place only in the endosperm of the developing seed. Although far from complete, a picture of how imprinting operates in flowering plants has begun to emerge. Imprinted genes on either the maternal or paternal side are marked and silenced in a process involving DNA methylation and chromatin condensation. In addition, on the maternal side, imprinted genes are most probably under control of the polycomb FIS genes.
authors.affiliation: Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
authors.forename: Rinke
authors.initials: R
authors.lastname: Vinkenoog
authors.forename: Catherine
authors.initials: C
authors.lastname: Bushell
authors.forename: Melissa
authors.initials: M
authors.lastname: Spielman
authors.forename: Sally
authors.initials: S
authors.lastname: Adams
authors.forename: Hugh G
authors.initials: HG
authors.lastname: Dickinson
authors.forename: Rod J
authors.initials: RJ
authors.lastname: Scott
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development; D019175:DNA Methylation; D035264:Flowers / Q000502:physiology*; D018392:Genomic Imprinting / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism
chemical_list: D010940:Plant Proteins