Comprehensive identification and analysis of extracellular signaling molecules involved in vascular tissue formation

1. TDIF的分离和鉴定：我们成功地分离了TDIF，它由12个氨基酸残基和两个羟脯氨酸残基组成，并抑制导管分子分化。TDIF基因属于CLE基因家族。2. CLV 3肽的鉴定：我们检测了不同大小的CLV 3肽对茎分生组织形成的活性，发现具有2个羟脯氨酸残基的12个氨基酸是必需的并且足以抑制分生组织形成。3. CLE肽的各种功能：测试了26种化学合成的CLE肽对各种事件（包括管细胞分化）的活性，并发现了它们的特异性和冗余性。4.木质素同源基因的分析：我们在拟南芥基因组中发现了15个与木质素基因相关的基因，并分析了它们的表达模式。它们中的一些优先在血管组织中表达，而另一些则在不同的组织中表达，这表明它们具有不同的功能。5.使用基因诱捕线分析原形成层特异性基因：我们成功地分离了几个在原形成层中优先表达的基因。6.γ-谷氨酰水解酶（GGH）基因的分析：GGH 1是在原形成层中优先表达的基因之一。GGH缩短叶酸的聚谷氨酸盐类型的聚谷氨酸盐链。GGH 1、GGH 2和GGH 3的功能缺失和功能获得分析表明，这些基因参与了分生组织的形成。结合体外实验的结果，我们提出多聚谷氨酸型叶酸在维持分生组织干细胞中起着至关重要的作用。

1. Isolation and characterization of TDIF: We succeeded in isolating TDIF, which is composed of 12 amino acid residues with two hydroxyproline residues and suppresses tracheary element differentiation. The gene for TDIF belonged to the CLE gene family. 2. Identification of the CLV3 peptide: We examined the activity of various size of CLV3 peptides against the shoot meristem formation, and found that 12 amino acids with 2 hydroxyproline residues are necessary and sufficient to suppress the meristem formation. 3. Various functions of CLE peptides: Twenty six chemically synthesized CLE peptides were tested for activities for various events including tracheary element differentiation and found their specificity and redundancy. 4. Analysis of xylogen homologues: We found 15 genes related to the xylogen genes in Arabidopsis genome and examined their expression pattern. Some of them were expressed preferentially in vascular tissues, but the others were expressed in distinctive tissues, suggesting their distinctive functions. 5. Analysis of procambium-specific genes using a gene trap line: We succeeded in the isolation of several genes that are expressed in preferentially in the procambium. 6. Analysis of the gamma-glutamyl hydrolase (GGH) gene: GGH1 is one of the genes that are expressed preferentially in the procambium. GGH shortens polyglutamate chains of the poly glutamate type of folic acid. The loss-of-function and gain-of-function analyses of GGHI, GGH2 and GGH3 indicated that these genes are involved in meristem formation. Taken together with results from in vitro experiments, we proposed that the poly glutamate type of folic acid plays a critical role in maintenance of stem cells in meristem.