title: Plant stem cell maintenance by transcriptional cross-regulation of related receptor kinases.
abstract: The CLAVATA3 (CLV3)-CLAVATA1 (CLV1) ligand-receptor kinase pair negatively regulates shoot stem cell proliferation in plants. clv1 null mutants are weaker in phenotype than clv3 mutants, but the clv1 null phenotype is enhanced by mutations in the related receptor kinases BARELY ANY MERISTEM 1, 2 and 3 (BAM1, 2 and 3). The basis of this genetic redundancy is unknown. Here, we demonstrate that the apparent redundancy in the CLV1 clade is in fact due to the transcriptional repression of BAM genes by CLV1 signaling. CLV1 signaling in the rib meristem (RM) of the shoot apical meristem is necessary and sufficient for stem cell regulation. CLV3-CLV1 signaling in the RM represses BAM expression in wild-type Arabidopsis plants. In clv1 mutants, ectopic BAM expression in the RM partially complements the loss of CLV1. BAM regulation by CLV1 is distinct from CLV1 regulation of WUSCHEL, a proposed CLV1 target gene. In addition, quadruple receptor mutants are stronger in phenotype than clv3, pointing to the existence of additional CLV1/BAM ligands. These data provide an explanation for the genetic redundancy seen in the CLV1 clade and reveal a novel feedback operating in the control of plant stem cells.
authors.affiliation: Division of Biology 156-29, California Institute of Technology, Pasadena, CA 91125, USA Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA znimchuk@vt.edu.
authors.forename: Zachary L
authors.initials: ZL
authors.lastname: Nimchuk
authors.affiliation: Division of Biology 156-29, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Division of Biology 156-29, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Paul T
authors.initials: PT
authors.lastname: Tarr
authors.affiliation: Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA.
authors.forename: Brenda A
authors.initials: BA
authors.lastname: Peterson
authors.affiliation: Division of Biology 156-29, California Institute of Technology, Pasadena, CA 91125, USA Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Elliot M
authors.initials: EM
authors.lastname: Meyerowitz
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation / Q000235:genetics / Q000502:physiology*; D003433:Crosses, Genetic; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology*; D005822:Genetic Vectors / Q000235:genetics; D005838:Genotype; D018398:Homeodomain Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D009154:Mutation / Q000235:genetics; D030821:Plants, Genetically Modified; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D013234:Stem Cells / Q000502:physiology*
chemical_list: C118167:AT2G27250 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; C116421:WUSCHEL protein, Arabidopsis; D020794:Receptor Protein-Tyrosine Kinases; C519658:BAM1 protein, Arabidopsis; C519659:BAM2 protein, Arabidopsis; C581880:BAM3 protein, Arabidopsis; C118166:CLV1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases
keywords: Arabidopsis thaliana; CLV1; Plant development; Receptor kinase; Stem cells