Functional analysis of novel transcription factors of Arabidopsis thaliana involved in the regulation of nutrient storage.

1. ASML 1/WRI 1参与种子油积累的作用靶点及功能拟南芥AP 2型转录激活因子ASML 1/WRI 1在种子成熟期表达。我们发现质体中许多参与脂肪酸合成的基因是ASML 1/WRI 1的直接靶基因，并鉴定了共有的DNA结合序列。ASML 1/WRI 1在种子发育过程中促进碳流向油的合成，而ASML 1/WRI 1亚家族的另外两个成员可能在营养组织中调节脂肪酸的合成。2. ASML 2与CCT结构域的功能虽然我们发现ASML 2的CCT结构域与控制种子成熟的ABI 3的B3结构域相互作用，但ASML 2基因在种子成熟期仅微弱表达。相反，ASML 2-Like I也激活糖诱导基因并与ABI 3和HSI 2相互作用，在种子成熟期表达。我们鉴定了一个ASML 2-L1基因缺失的突变体. HSI 2和HSL 1对种子成熟程序的抑制HSI 2和HSL 1是抑制糖诱导基因表达的新型B3-β转录抑制因子。两个基因敲除的幼苗（KK突变体）表达胚胎和种子成熟基因，并在萌发后7天停止生长，这表明HSI 2/HSL 1是抑制种子成熟程序和萌发后向营养生长过渡所必需的。这表明，C-末端的HSI 2的阻遏基序是不是必不可少的这一功能。我们通过使用hsi 2敲除植物与DEX诱导的针对HSL 1的RNAi来鉴定HSL 1的靶标候选物，这使得我们能够通过DEX处理诱导KK突变体表型。

1.Targets and function of ASML1/WRI1 involved in seed oil accumulation.An AP2-type transcriptional activator ASML1/WRI1 of Arabidopsis thaliana is expressed during seed maturation phase. We found that many genes involved in fatty acid synthesis in plastids are direct targets of ASML1/WRI1 and identified consensus DNA binding sequence. While ASML1/WRI1 fascillitates flow of carbon to oil synthesis during seed development, two other ASML1/WRI1 subfamily members are likely to regulate fatty acid synthesis in vegetative tissues2.Function of ASML2 with the CCT domainAlthough we found that CCT domain of ASML2 interacts with B3 domain of ABI3 that controls seed maturation, gene for ASML2 was expressed only weakly during seed maturation phase. Instead, ASML2-Like I that also activates sugar-inducible gene and interacts with ABI3 and HSI2 is expressed during seed maturation phase. We identified a mutant with disruption of ASML2-L1 gene.3. Repression of seed maturation program by HSI2 and HSL1HSI2 and HSL1 are novel B3-EAR transcriptional repressors that repress sugar-inducible gene expression. Seedlings with knockouts of both genes (KK mutant) express embryonic and seed maturation genes and stop growth 7 days after germination, suggesting that HSI2/HSL1 are essential for the repression of seed maturation program and transition to vegetative growth after germination. It was suggested that the C-terminal EAR repression motif of HSI2 is not essential for this function. We identified candidates of targets of HSL1 by using hsi2 knockout plants with DEX-inducible RNAi for HSL1 which enabled us to induce KK mutant phenotype by treatment with DEX.