PLANT EXPORTIN-T MUTATION DISRUPTS MERISTEM DEVELOPMENT

拟南芥暂停基因（psd）的突变导致茎尖分生组织中未分化细胞的死亡，叶片原始细胞的产生延迟，以及叶片同一性的异时性转变。PSD编码一个export -t的同源基因，一个成熟tRNA分子核输出所需的基因。由于在多细胞生物中很少有输入/输出蛋白家族成员的特征，因此将采取几种方法来了解PSD在拟南芥病发展中的作用。具体:1) PSD表达的空间和时间要求将取决于mRNA和蛋白表达模式的特征,有针对性的PSD基因的表达,2)将用于测定tRNA基因和分子分析导出和决定的影响PSD突变基因参与meristern发展,叶子开始,和相变,3)潜在的下游因素将在屏幕上孤立的增强和抑制PSD的表现型。这些实验将为多能细胞的维持和分化以及发育“时钟”的调节提供见解。它们也将为多细胞生物发育过程中核转运机制的体内分析提供难得的机会。

Mutations in the Arabidopsis pauses (psd) gene result in the death of undifferentiated cells in the shoot apical meristem, a delay in the production of leaf primordial, and heterochronix shifts in leaf identity. PSD encodes a homologue of exportin-t, a gene required for the nuclear export of mature tRNA molecules. As very few members of the importin/ exportin family have been characterized in multi cellular organisms, several approaches will be taken to understand the role of PSD in Arabidosis development. Specifically: 1) the spatial and temporal requirements for PSD expression will be determined by characterization of the mRNA and protein expression patterns and by targeted expression of the PSD gene, 2) genetic and molecular analysis will be used to assay tRNA export and to determine the effect of the PSD mutation on genes involved in meristern development, leaf initiate, and phase change, and 3) potential downstream factors will be isolated in a screen for enhances and suppressors of the PSD phenotype. These experiments will offer insight into the maintenance and differentiation of pluripotent cells and the regulation of developmental 'clocks.' They will also provide a rare opportunity for the in vivo analysis of nuclear transport machinery during the development of a multi cellular organism.