CORONA, a member of the class III homeodomain leucine zipper gene family in arabidopsis, regulates stem cell specification and organogenesis
CORONA, a member of the class III homeodomain leucine zipper gene family in arabidopsis, regulates stem cell specification and organogenesis
复制标题
DOI：
10.1105/tpc.104.026179
复制
发表时间：
2005-03-01
期刊：
影响因子：
11.6
通讯作者：
Clark, SE
中科院分区：
文献类型：
--
作者：
Green, KA;Prigge, MJ;Clark, SE
茎分生组织的器官发生需要干细胞特化和分化之间的微妙平衡。在拟南芥中，WUSCHEL（WUS）是促进干细胞身份的关键因子，而CLAVATA（CLV 1、CLV 2和CLV 3）基因座似乎通过抑制WUS表达来促进分化。在筛选clv 1突变体的突变修饰中，我们已经确定了一种新的分生组织发育调节因子，我们称之为CORONA（CNA）。而cna单突变体植物表现出微妙的缺陷分生组织的发展，clv cna双突变体发展大规模扩大的顶端，显示早期损失的器官发生，错误表达的WUS和CLV 3，并最终分化的整个顶端。通过定位克隆分离CNA基因，发现其编码III类同源结构域Leu拉链蛋白。在一个未知功能的保守结构域中发现了一个导致显性阴性cna-1等位基因的错义突变，一个可能的无效等位基因显示出相似但较弱的表型。CNA在发育中的维管组织中表达，通过芽和花分生组织扩散，以及在发育中的雄蕊和心皮中表达。我们对野生型、CLV和CLV cna植物中WUS表达的分析表明，与目前的模型相反，WUS对于干细胞特化既不是必要的也不是充分的，并且WUS和CLV 3都不是干细胞身份的标志物。我们认为CNA与CLV基因座平行发挥功能，以促进器官形成。
Organogenesis at the shoot meristern requires a delicate balance between stem cell specification and differentiation. In Arabidopsis thaliana, WUSCHEL (WUS) is a key factor promoting stem cell identity, whereas the CLAVATA (CLV1, CLV2, and CLV3) loci appear to promote differentiation by repressing WUS expression. In a screen for mutations modifying clv1 mutants, we have identified a novel regulator of meristern development we term CORONA (CNA). Whereas cna single mutant plants exhibit subtle defects in meristern development, clv cna double mutants develop massively enlarged apices that display early loss of organogenesis, misexpression of WUS and CLV3, and eventual differentiation of the entire apex. The CNA gene was isolated by positional cloning and found to encode a class III homeodomain Leu zipper protein. A missense mutation resulting in the dominant-negative cna-1 allele was identified in a conserved domain of unknown function, and a likely null allele was shown to display a similar but weaker phenotype. CNA is expressed in developing vascular tissue, diffusely through shoot and flower meristems, and within developing stamens and carpels. Our analysis of WUS expression in wild-type, clv, and clv cna plants revealed that, contrary to current models, WUS is neither necessary nor sufficient for stem cell specification and that neither WUS nor CLV3 is a marker for stem cell identity. We propose that CNA functions in parallel to the CLV loci to promote organ formation.