CLAVATA1 dominant-negative alleles reveal functional overlap between multiple receptor kinases that regulate meristem and organ development.
The CLAVATA1 (CLV1) receptor kinase controls stem cell number and differentiation at the Arabidopsis shoot and flower meristems. Other components of the CLV1 signaling pathway include the secreted putative ligand CLV3 and the receptor-like protein CLV2. We report evidence indicating that all intermediate and strong clv1 alleles are dominant negative and likely interfere with the activity of unknown receptor kinase(s) that have functional overlap with CLV1. clv1 dominant-negative alleles show major differences from dominant-negative alleles characterized to date in animal receptor kinase signaling systems, including the lack of a dominant-negative effect of kinase domain truncation and the ability of missense mutations in the extracellular domain to act in a dominant-negative manner. We analyzed chimeric receptor kinases by fusing CLV1 and BRASSINOSTEROID INSENSITIVE1 (BRI1) coding sequences and expressing these in clv1 null backgrounds. Constructs containing the CLV1 extracellular domain and the BRI1 kinase domain were strongly dominant negative in the regulation of meristem development. Furthermore, we show that CLV1 expressed within the pedicel can partially replace the function of the ERECTA receptor kinase. We propose the presence of multiple receptors that regulate meristem development in a functionally related manner whose interactions are driven by the extracellular domains and whose activation requires the kinase domain.
Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor 48109-1048, USA.
Anne
A
Diévart
Monica
M
Dalal
Frans E
FE
Tax
Alexzandria D
AD
Lacey
Alison
A
Huttly
Jianming
J
Li
Steven E
SE
Clark
D000483:Alleles; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005799:Genes, Dominant / Q000235:genetics; D018519:Meristem / Q000235:genetics / Q000254:growth & development*; D009154:Mutation; D010641:Phenotype; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D011993:Recombinant Fusion Proteins; C036483:T-DNA; D011494:Protein Kinases; D020794:Receptor Protein-Tyrosine Kinases; C108270:BRI1 protein, Arabidopsis; C118166:CLV1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases