Polycomb group genes control developmental timing of endosperm.
Polycomb (PcG) group proteins form modular complexes, which maintain repressed transcriptional states of target genes across cell divisions. As PcG complexes provide a memory of cell fate, such proteins might control temporal aspects of development. Loss-of-function of any of the FERTILIZATION INDEPENDENT SEED (FIS) PcG genes perturbs endosperm development. In this report we provide a detailed analysis of the phenotype of fis endosperm development using molecular and cellular markers. Wild type (WT) endosperm development undergoes a series of four major developmental phases timed by successive synchronous nuclei division. In fis endosperm the transition from phase 1, marked by a synchronous mode of nuclei divisions to phase 2, corresponding to the establishment of three mitotic domains, is absent. Accordingly, the expression of seven markers of phase 1 and phase 2 is temporally perturbed. In spite of such changes, specific sequences of developmental events still take place as in the WT. Overall, fis mutations are heterochronic mutations that cause a temporal deregulation in the ontogenic sequence of endosperm development.
Ingouff
Mathieu
M
European Molecular Biology Organization (EMBO) YIP Team, Unité Mixte de Recherche 5667, Ecole Normale Supérieure de Lyon, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université de Lyon I, France.
Haseloff
Jim
J
Berger
Frédéric
F
D017360:Arabidopsis / Q000196:embryology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology; D017343:Genes, Plant; D005819:Genetic Markers; D005810:Multigene Family; D009154:Mutation; D010641:Phenotype; D030821:Plants, Genetically Modified; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology; D012639:Seeds / Q000254:growth & development*
D029681:Arabidopsis Proteins; D005819:Genetic Markers; D012097:Repressor Proteins