title: Vascular signalling mediated by ZWILLE potentiates WUSCHEL function during shoot meristem stem cell development in the Arabidopsis embryo.
abstract: Stem cells are maintained in an undifferentiated state by signals from their microenvironment, the stem cell niche. Despite its central role for organogenesis throughout the plant's life, little is known about how niche development is regulated in the Arabidopsis embryo. Here we show that, in the absence of functional ZWILLE (ZLL), which is a member of the ARGONAUTE (AGO) family, stem cell-specific expression of the signal peptide gene CLAVATA3 (CLV3) is not maintained despite increased levels of the homeodomain transcription factor WUSCHEL (WUS), which is expressed in the organising centre (OC) of the niche and normally promotes stem cell identity. Tissue-specific expression indicates that ZLL acts to maintain the stem cells from the neighbouring vascular primordium, providing direct evidence for a non-cell-autonomous mechanism. Furthermore, mutant and marker gene analyses suggest that during shoot meristem formation, ZLL functions in a similar manner but in a sequential order with its close homologue AGO1, which mediates RNA interference. Thus, WUS-dependent OC signalling to the stem cells is promoted by AGO1 and subsequently maintained by a provascular ZLL-dependent signalling pathway.
authors.affiliation: Faculty of Biology, Schaenzlestrasse 1, University of Freiburg, D-79104 Freiburg, Germany.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Tucker
authors.forename: Annika
authors.initials: A
authors.lastname: Hinze
authors.forename: Elise J
authors.initials: EJ
authors.lastname: Tucker
authors.forename: Shinobu
authors.initials: S
authors.lastname: Takada
authors.forename: Gerd
authors.initials: G
authors.lastname: Jürgens
authors.forename: Thomas
authors.initials: T
authors.lastname: Laux
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism*; D047108:Embryonic Development; D018398:Homeodomain Proteins / Q000378:metabolism*; D018519:Meristem / Q000254:growth & development* / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012639:Seeds / Q000166:cytology* / Q000378:metabolism; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism; D060565:Argonaute Proteins
chemical_list: D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; D011993:Recombinant Fusion Proteins; C116421:WUSCHEL protein, Arabidopsis; C529694:AT5G43810 protein, Arabidopsis; D060565:Argonaute Proteins