Molecular Mechanisms Controlling Tissue and Organ Differentiation

根据最初提出的研究计划，这些调查人员小组获得了如下所述的结果。Machida分离并鉴定了不对称叶片2（ASYMMETRIC LEAVES2, AS2）和AS1基因。由这些基因编码的蛋白质相互关联，并在叶片发育过程中作为转录抑制因子抑制class1 knox同源盒基因的表达。Tsukaya克隆了一个专门负责叶片横向扩张的AN基因，并证明了AN蛋白在氨基酸序列上与CtBP（c -末端结合蛋白）相似。他的研究小组还表明，AN通过调节植物细胞皮层微管的形成来控制细胞壁的结构。Nakamura分离了许多拟南芥突变体，其中SPO:: LUC报告基因的糖依赖性表达受到突变的影响。这些突变体包括那些只表现出异常糖反应的突变体和那些对ABA和糖也改变反应的突变体。因此，这些反应必须有两个独立的途径。Shimamoto试图鉴定可能决定水稻短日开花反应的基因，并发现CO基因的水稻同源基因抑制FT基因的水稻同源基因的表达，而FT基因负责水稻短日开花。Umeda证实CDKB2/cycline B复合物直接参与水稻细胞的分化和细胞周期的进展。他还表明，水稻CAK在体外没有细胞分裂素的情况下具有形成愈伤组织的能力。Nishitani表明拟南芥有33个属于EXGT家族的基因，这些基因以个体方式控制这些基因的组织特异性表达。我们的团队从一般申请者中挑选成员，为植物的形态发生和分化提供了足够的贡献。

Following the research plan proposed initially, the group of these investigators have obtained results described below. Machida isolated and characterized the ASYMMETRIC LEAVES2(AS2) and AS1 genes. Proteins that are encoded by these genes were shown to be associated each other and to act as transcription repressors against expression of class1 knox homeobox genes during leaf development. Tsukaya cloned the AN gene that is responsible specifically for lateral expansion of leaf lamina and that demonstrated that AN protein is similar in terms of amino acid sequence to CtBP(C-terminal binding protein). His group also showed that AN controls structures of cell walls through modulation of formation of cortical microtubules of plant cells. Nakamura isolated a number of Arabidopsis mutants in which sugar-dependent expression of the SPO : : LUC reporter gene is affected by the mutations. These mutants were shown to include ones that exhibited only an abnormal sugar response and ones that also altered responses to ABA as well as sugar. Thus, there must be two independent pathways for these responses. Shimamoto attempted to identify genes that may determine the short-day response of flowering of rice and showed that the rice homolog of the CO gene represses expression of the rice homolog of the FT gene, which is responsible for short-day flowering of rice. Umeda demonstrated that CDKB2/cycline B complex is involved directly in differentiation of rice cells as well as progression of cell cycle. He also showed that a rice CAK has an ability to form calli without cytokinin in vitro. Nishitani showed that Arabidopsis has 33 gene that belong to the EXGT family and that these genes are controlled in individual manners for tissue-specific expression of these genes. Our group including members who had been selected from general applicants has provided sufficient contributions to morphogenesis and differentiation of plants.