Molecular Biological Studies on the Regulation of MeEthionine Biosynthesis Using an Arabidopsis thaliana Mutant.

使用拟南芥突变体调节甲硫氨酸生物合成的分子生物学研究。

• 批准号: 09440262
• 负责人: NAITO Satoshi
• 金额: $ 6.72万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09440262/
• 关键词: Arabidopsis thaliana; methionine; amino acid synthesis; mRNA accumulation; systathionine gamma-synthase; mutant; メチオニン生合成; 突然変異株; エチオニン耐性; シスタチオニンγ-シンターゼ; シスタチオニンγーシンターゼ

In order to know the molecular mechanism of the regulation of methionine biosynthesis in higher plants, Arabidopsis mutants, mtol, that over-accumulate soluble methionine was studied. The mtol mutant plants accumulate up to 40-fold higher concentrations of soluble methionine in young rosette leaves, whereas the accumulation of other amino acids of the aspartate family were not appreciably different from wild-type plants. Therefore, the biochemical lesion carried by the mtol mutant was suggested to be resided in one of the later steps in the pathway. Accumulation of mRNA for cystathionine gamma-synthase (CGS), which has been suggested to be a key enzyme in methionine biosynthesis, was higher in mtol mutant as compared to wild-type plants. When wild0type plants were cultured in the presence of methionine, the accumulation of CGS mRNA was reduced, whereas no such effect was observed in the mtol mutant plants. Therefore it was suggested that wild-type plants have a mechanism to down-regulate the accumulation of CGS mRNA in response to methionine excess conditions. Genetic mapping and sequence analyses revealed that the mtol mutant bears mutations in the coding region of CGS gene. Transient expression analyses indicated that the mtol mutation affects the stability of CGS mRNA.

为了了解高等植物中蛋氨酸生物合成调控的分子机制，对过量积累可溶性蛋氨酸的拟南芥突变体mtol进行了研究。mtol突变体植物在幼莲座叶中积累高达40倍的可溶性甲硫氨酸浓度，而天冬氨酸家族的其他氨基酸的积累与野生型植物没有明显不同。因此，mtol突变体所携带的生化损伤被认为是位于该途径的后续步骤之一。与野生型植物相比，mtol突变体中胱硫醚γ-合酶（CGS）的mRNA积累更高，CGS已被认为是甲硫氨酸生物合成的关键酶。当野生型植物在甲硫氨酸存在下培养时，CGS mRNA的积累减少，而在mtol突变体植物中没有观察到这种效果。因此，表明野生型植物具有响应于甲硫氨酸过量条件而下调CGS mRNA积累的机制。基因定位和序列分析表明，突变株的CGS基因编码区发生了突变。瞬时表达分析表明，mtol突变影响CGS mRNA的稳定性。

项目成果

K.Ohshim: "Isolation of a mutant of Arabidopsis thaliana carrying two simultaneous mutations affecting tobacco mosaic virus multiplication within a single cell" Virology. 243・2. 472-481 (1998)

K.Ohshim：“分离携带两个同时影响烟草花叶病毒在单细胞内繁殖的突变体”病毒学243·2（1998）。

K. T.Yoshida: "Temporal and spatial patterns of accumulation of the transcript of myo-Inositol-1-phosphate synthase and phytin-containing particles during seed development in rice." Plant Physiol.119-1. 65-72 (1999)

K. T.Yoshida：“在水稻种子发育过程中，肌醇 1-磷酸合酶和含有植酸钙的颗粒的转录物积累的时间和空间模式。”

E.Nambara: "Characterization of an Arabidopsis thaliana mutant that has a defect in ABA accumulation : ABA-dependent and ABA-independent accumulation of free amino acids during dehydration" Plant Cell Physiology. 39・8. 853-858 (1998)

E.Nambara：“ABA 积累缺陷的拟南芥突变体的表征：脱水过程中游离氨基酸的 ABA 依赖性和非 ABA 依赖性积累”《植物细胞生理学》39·8 (1998)。

D.Saisho: "Characterization of the gene family for altemative oxidase from Arabidopsis thaliana.." Plant Mol. Biol.35-5. 585-596 (1997)

D.Saisho：“拟南芥替代氧化酶基因家族的表征..”植物分子。

T.Fujiwara, A.Matsui, M.Y.Hirai, A.Furuhashi, M.Awazuhara, C.Honda, H.Kim, K.Noguchi, N.Shibagaki, M.Yasumori, H.Hayashi, S.Naito and M.Chino: "Genetic and physiological approaches toward understanding the mechanism underlying the sulfur-regulated express

T.Fujiwara、A.Matsui、M.Y.Hirai、A.Furuhashi、M.Awazuhara、C.Honda、H.Kim、K.Noguchi、N.Shibagaki、M.Yasumori、H.Hayashi、S.Naito 和 M.Chino