Imprinting of the polycomb group gene MEDEA serves as a ploidy sensor in Arabidopsis.
Balanced maternal and paternal genome contributions are a requirement for successful seed development. Unbalanced contributions often cause seed abortion, a phenomenon that has been termed "triploid block." Misregulation of imprinted regulatory genes has been proposed to be the underlying cause for abnormalities in growth and structure of the endosperm in seeds with deviating parental contributions. We identified a mutant forming unreduced pollen that enabled us to investigate direct effects of unbalanced parental genome contributions on seed development and to reveal the underlying molecular mechanism of dosage sensitivity. We provide evidence that parent-of-origin-specific expression of the Polycomb group (PcG) gene MEDEA is causally responsible for seed developmental aberrations in Arabidopsis seeds with increased paternal genome contributions. We propose that imprinted expression of PcG genes is an evolutionary conserved mechanism to balance parental genome contributions in embryo nourishing tissues.
Department of Biology and Zurich-Basel Plant Science Center, Swiss Federal Institute of Technology, Zurich, Switzerland.
Aleksandra
A
Erilova
Lynette
L
Brownfield
Vivien
V
Exner
Marisa
M
Rosa
David
D
Twell
Ortrun
O
Mittelsten Scheid
Lars
L
Hennig
Claudia
C
Köhler
D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003433:Crosses, Genetic; D004171:Diploidy; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005816:Genetic Complementation Test; D018392:Genomic Imprinting / Q000235:genetics*; D006720:Homozygote; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D011003:Ploidies; D011058:Pollen / Q000166:cytology / Q000235:genetics; D063146:Polycomb-Group Proteins; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000254:growth & development
D029681:Arabidopsis Proteins; D026161:MADS Domain Proteins; C111712:MEA protein, Arabidopsis; C475745:PHERES1 protein, Arabidopsis; D063146:Polycomb-Group Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins