REV Gene Family and Meristem Initiation

拟南芥在地上的所有胚胎后发育都是通过茎和花分生组织器官的形成进行的。因此，芽和花的分生组织的形成是随后的模式形成和细胞分化的基本先决条件。REVOLUTA （REV）基因在侧枝和花分生组织形成中的作用最近被描述。遗传和分子分析表明，REV在侧分生组织起始过程的早期起作用，并且至少间接地对已知的分生组织调节因子（如CLV位点、WUS和STM）的侧位重新激活是必需的。REV编码一个III型HD-zip蛋白，包含一个假定的dna结合同源结构域、一个可能参与二聚化的亮氨酸拉链结构域和一个START固醇/脂质结合结构域。其他分析表明，REV也是正常血管器官发育所必需的。与这些发育作用一致，REV在维管组织、器官和侧边分生组织中表达较早。REV是拟南芥中一个由5个基因组成的密切相关基因家族的成员。rev突变表型的可变表达性和其他基因家族成员的功能缺失等位基因的表型缺失表明，这些基因可能表现出功能冗余。事实上，通过对功能获得等位基因的分析，其他基因家族成员也与器官发育/极性和血管发育有关。功能冗余可能在植物基因组中非常普遍，其中基因复制水平明显高于动物基因组。然而，在整个基因家族中，人们对功能规范的本质知之甚少，这个基因家族已经进化出了多种发育作用。因此，REV基因家族是一个很好的系统，可以用来确定不同基因家族成员之间的关系，以及每个基因家族成员在植物发育中扮演的潜在重叠角色。本提案旨在利用REV基因家族来表征一个功能相关的基因家族，以及推进对侧分生组织发育的理解。每个家庭成员的功能丧失等位基因已经被确定，遗传分析将确定每个基因对哪个发育过程有贡献。将评估每个基因的mRNA表达模式，以及每个基因编码的蛋白质的功能等效性。潜在的下游目标将被描述。这项工作将提供一个关键的全面了解的关系，也许起源，一个功能相关的基因家族。这将对其他植物发育系统中冗余基因的作用具有重要意义。此外，侧边分生组织起始的关键调节因子的作用将被表征。

0131492Clark All above ground post-embryonic development in Arabidopsis occurs through the initiation of organs at shoot and flower meristems. Thus, the initiation of shoot and flower meristems is a fundamental prerequisite for subsequent pattern formation and cell differentiation. The role of the REVOLUTA (REV) gene in the initiation of lateral shoot and flower meristems has recently been described. Genetic and molecular analysis suggested that REV acts early in the process of lateral meristem initiation, and is required, at least indirectly, for the reactivation of known meristem regulators, such as the CLV loci, WUS and STM, at lateral positions. REV encodes a type III HD-zip protein, containing a putative DNA-binding homeodomain, a leucine zipper domain likely involved in dimerization, and a START sterol/lipid binding domain. Other analysis has revealed that REV is also required for normal vascular organ development. Consistent with these developmental roles, REV is expressed early in vascular tissue, organs and lateral meristems.REV is a member of a closely related gene family consisting of five genes in Arabidopsis. The variable expressivity of rev mutant phenotypes and the lack of phenotypes for loss-of-function alleles of other gene family members suggest that these genes may exhibit functional redundancy. Indeed, other gene family members have been implicated in organ development/polarity and vascular development through the analysis of gain-of-function alleles. Functional redundancy is likely to be very common among plant genomes, where the level of gene duplication is significantly higher than among animal genomes. However, little is known about the nature of functional specification among an entire gene family that has evolved multiple developmental roles. The REV gene family thus makes an excellent system in which to determine the relationships between the various gene family members and the potentially overlapping roles that each plays in plant development.This proposal seeks to use the REV gene family to characterize a functionally interrelated gene family, as well as advance understanding of lateral meristem development. Loss-of-function alleles have been identified for each family members and genetic analysis will determine to which development processes each gene contributes. The mRNA expression patterns of each gene will be assessed, as well as the functional equivalence of the proteins encoded by each gene. Potential downstream targets will be characterized. This work will provide a critical comprehensive understanding of the relationships, and perhaps origins, of a functionally interrelated gene family. This will be of significance to other plant developmental systems in which the action of redundant genes are important. Furthermore, the roles of key regulators of lateral meristem initiation will be characterized.