Deyoung Brody J, Clark Steven E
Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1048, USA.
Genetics. 2008 Oct;180(2):895-904. doi: 10.1534/genetics.108.091108. Epub 2008 Sep 9.
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.
CLAVATA1（CLV1）受体激酶调控拟南芥茎尖和花分生组织中的干细胞特化。大多数clv1等位基因是显性负效的，而clv1无效等位基因的表型较弱，这表明有其他受体在并行发挥作用。我们已鉴定出两个这样的并行受体，即BAM1和BAM2。我们发现clv1无效等位基因表型较弱依赖于BAM活性，bam clv双突变体在干细胞特化方面表现出严重缺陷。此外，分生组织中的BAM活性依赖于CLV2，CLV2是CLV1功能部分所需的。另外，clv1突变体增强了许多Bam（-）器官的表型，这表明与当前认知相反，CLV1的功能并非分生组织所特有的。CLV3编码一种小的分泌肽，作为CLV1的配体。clv3突变导致干细胞积累增加。令人惊讶的是，bam1和bam2突变体抑制了clv3突变体的表型。我们推测，除了在分生组织中心具有冗余功能外，BAM1和BAM2还在分生组织侧翼起到隔离CLV3样配体的作用。
