BAM receptors regulate stem cell specification and organ development through complex interactions with CLAVATA signaling.
The CLAVATA1 (CLV1) receptor kinase regulates stem cell specification at shoot and flower meristems of Arabidopsis. Most clv1 alleles are dominant negative, and clv1 null alleles are weak in phenotype, suggesting additional receptors functioning in parallel. We have identified two such parallel receptors, BAM1 and BAM2. We show that the weak nature of the phenotype of clv1 null alleles is dependent on BAM activity, with bam clv mutants exhibiting severe defects in stem cell specification. Furthermore, BAM activity in the meristem depends on CLV2, which is required in part for CLV1 function. In addition, clv1 mutants enhance many of the Bam(-) organ phenotypes, indicating that, contrary to current understanding, CLV1 function is not specific to the meristem. CLV3 encodes a small, secreted peptide that acts as the ligand for CLV1. Mutations in clv3 lead to increased stem cell accumulation. Surprisingly, bam1 and bam2 mutants suppress the phenotype of clv3 mutants. We speculate that in addition to redundant function in the meristem center, BAM1 and BAM2 act to sequester CLV3-like ligands in the meristem flanks.
Deyoung
Brody J
BJ
Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1048, USA.
Clark
Steven E
SE
D000483:Alleles; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D018519:Meristem / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D038081:Organogenesis; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*
C118167:AT2G27250 protein, Arabidopsis; D029681:Arabidopsis Proteins; C401621:CLV2 protein, Arabidopsis; D008565:Membrane Proteins; D020794:Receptor Protein-Tyrosine Kinases; C519658:BAM1 protein, Arabidopsis; C519659:BAM2 protein, Arabidopsis; C118166:CLV1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases
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