Role of the ZWILLE gene in the regulation of central shoot meristem cell fate during Arabidopsis embryogenesis.
Postembryonic development in higher plants is marked by repetitive organ formation via a self-perpetuating stem cell system, the shoot meristem. Organs are initiated at the shoot meristem periphery, while a central zone harbors the stem cells. Here we show by genetic and molecular analyses that the ZWILLE (ZLL) gene is specifically required to establish the central-peripheral organization of the embryo apex and that this step is critical for shoot meristem self-perpetuation. zll mutants correctly initiate expression of the shoot meristem-specific gene SHOOT MERISTEMLESS in early embryos, but fail to regulate its spatial expression pattern at later embryo stages and initiate differentiated structures in place of stem cells. We isolated the ZLL gene by map-based cloning. It encodes a novel protein, and related sequences are highly conserved in multicellular plants and animals but are absent from bacteria and yeast. We propose that ZLL relays positional information required to maintain stem cells of the developing shoot meristem in an undifferentiated state during the transition from embryonic development to repetitive postembryonic organ formation.
Moussian
B
B
Lehrstuhl für Entwicklungsgenetik, Auf der Morgenstelle 1, D-72076 Tübingen, Germany.
Schoof
H
H
Haecker
A
A
Jürgens
G
G
Laux
T
T
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins; D002454:Cell Differentiation; D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D017343:Genes, Plant / Q000235:genetics / Q000502:physiology*; D018398:Homeodomain Proteins / Q000235:genetics; D018519:Meristem / Q000166:cytology / Q000196:embryology* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics* / Q000502:physiology; D018520:Plant Shoots / Q000166:cytology / Q000196:embryology / Q000648:ultrastructure; D012333:RNA, Messenger / Q000032:analysis; D018749:RNA, Plant / Q000032:analysis; D017422:Sequence Analysis, DNA; D060565:Argonaute Proteins
D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; C097496:STM protein, Arabidopsis; C529694:AT5G43810 protein, Arabidopsis; D060565:Argonaute Proteins