Molecular Mechanisms Controlling Embryo and Meristem Formation

本项目旨在了解植物组成多细胞体的遗传调控系统，特别是胚胎发育和分生组织形成与维持的遗传调控系统。主要研究结果如下：冈田组：对一个根分生组织缺陷突变体hlr的分析表明，它在一个蛋白质复合物亚基上发生了突变。这是一个新的观察结果，表明程序性蛋白质降解是维持根分生组织结构和功能所必需的。本研究还检测了控制细胞极化伸长的FTR基因、控制表皮细胞规格的CPC基因、控制雄性配子体的KOM基因和控制茉莉酸合成和花药开放的DAD1基因。2. Araki组研究了与茎尖分生组织（SAM）形成相关的FAS1和fas2基因。这些基因编码染色质组装因子（CAF）亚基。该小组还分析了一个关键的开花基因FT，并发现了抑制或增强过表达FT的新基因。Kakimoto小组鉴定的异戊烯基转移酶是细胞分裂素生物合成的关键酶。该小组还研究了细胞分裂素受体及其下游信号通路。4. Shinozaki组：该组构建了大量转座子标记的拟南芥系，研究了一组雄性不育、胚胎致死、叶片形态畸形的突变体。5. Sugiyama小组研究了一组突变体，这些突变体在愈伤组织的茎和根再生过程中表现出温度依赖性缺陷。他们克隆了其中一个基因SRD2，并证明该基因与snrna的转录激活有关。6. Tasaka组研究了胚胎发生过程中控制SAM形成的基因调控网络。他们研究了CUC1和2基因，发现它们调节其他SAM基因，如STM和KNOX。7. Fukuda组：利用Xinnia的同步细胞培养系统和尖端程序，鉴定了大量叶片细胞形成维管细胞所需的基因。细胞自溶所需的基因也被克隆。8. Matsuoka组研究了多种水稻胚型突变体，表现为多芽、无芽、器官形态异常和分生组织取向异常。上述研究报告发表在期刊或国际或国家研讨会上。少

This project aimed to understand the genetic regulatory systems which contribute to make up multi-cellular body of plants, especially in the embryo development and in the meristem formation and maintenance. The major results are as follows.1. Okada group : Analysis of a root meristem-defective mutant, hlr, showed that it has a mutation in a subunit of proteosome complex. This is a novel observation showing that programmed protein degradation is required for maintaining structure and function of the root meristem. This group also examined FTR gene controlling polarized cell elongation, CPC gene controlling epidermal cell specification, KOM gene controlling male gametophyte, and DAD1 gene controlling jasmonic acid synthesis and anther opening. 2. Araki group studied FAS1 and 2 genes responding to the formation of shoot apical meristem (SAM). The genes encode subunits of chromatin assembly factor (CAF). The group also analyzed a key flowering gene, FT, and identified new genes suppressing … More or enhancing the effect of overexpressing FT. 3. Kakimoto group identified isopentenyl transferases are the key enzyme in the cytokinin biosynthesis. The group also studied cytokinin receptors and their downstream signaling pathways. 4. Shinozaki group : The group constructed a large number of transposon-tagged Arabidopsis lines, and studied a set of mutants showing male sterile, embryo lethal, leaf malmorphology. 5. Sugiyama group studied a set of mutnats showing temperature-dependent defects in the shoot and root regeneration process from callus. They cloned one of the genes, SRD2, and shown the gene is related to the transcriptional activation of snRNAs. 6. Tasaka group examined gene regulatory network controlling SAM formation in embryogenesis. They studied CUC1 and 2 genes and shown they regulate other SAM genes such as STM and KNOX. 7. Fukuda group : By using synchronized cell culture system of Xinnia and the tip-procedure, a large number of genes were identified which are required for vascular cell formation from leaf cells. Genes required for cell autolysis were also cloned. 8. Matsuoka group studied a variety of rice embryo pattern mutants showing many shoots, no shoots, aberrant organ form, and abberant orientation of meristem. The studies above were reported in journals or at international or national symposiums. Less