The study of cauces of mitochondrial cytopathy

线粒体细胞病变的病因研究

• 批准号: 05670679
• 负责人: ITO Michinori
• 金额: $ 1.34万
• 依托单位: University of Tokushima
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05670679/
• 关键词: Mitochondrial cytopathy; import of mitichonrial protein; pyruvate dehydrogenase; mitochondria; pyruvate dehydrogenase deficiency

Most of mitochondrial enzyme proteins are synthesized in the cytoplasm as precursor enzyme proteins and are subsequently imported into mitochondria to form mature enzyme proteins. The defect in this import system might be cause the mitochondrial cytopathy with sever clinical symptoms due to disturbance of mitochondrial functions. Recently we found the patient with defect of multiple mitochondrial enzymes containing pyruvate dehydrogenase (PDH) complex. In this project, to determine the primary defect in this patient we examined the import system of precursor proteins of PDH (pEla and pElb) into mitochondria in fibroblasts from the patient using cell-labeling and pulse-chase methods. The rates of import of pEla and pElb into mitochondria in fibroblasts from the patient decreased to about 40% and 63% of those in normal control fibroblasts, respectively. These results showed the defect of import system of Ela na Elb into mitochondria in this patient. Since the patient had not only the defect of PDH complex but also the defect of other mitochondrial enzymes and cDNAs for pEla and pElb in the patient had no mutation, the primary defect in this patient is in the import system of mitochondrila enzyme proteins into mitochondria.In anotheer study, we found a new 18bp insertion mutation in the gene for a subunit of PDH in afemale patient with PDH deficiency, the common cause of mitochondrial cytopathy, and the wide variation in the expression of mutant gene in cultcred cells from this patent. These results showed that female patients with PDH deficiency might be misdiagnosed only with enzymological diagnosis. Therefore, it is necessry to develop the new diagnosis method of PDH deficiency, such as DNA analysis.

大多数线粒体酶蛋白作为前体酶蛋白在细胞质中合成，随后输入线粒体形成成熟的酶蛋白。这一输入系统的缺陷可能导致线粒体功能紊乱而引起临床症状严重的线粒体细胞病。最近我们发现了一个病人有多种线粒体酶的缺陷，包括丙酮酸脱氢酶（PDH）复合物。在本项目中，为了确定该患者的主要缺陷，我们使用细胞标记和脉冲追踪方法检查了PDH前体蛋白（pEla和pElb）进入患者成纤维细胞线粒体的输入系统。pEla和pElb进入患者成纤维细胞线粒体的速率分别降低至正常对照成纤维细胞的约40%和63%。提示该患者存在Ela na Elb向线粒体输入系统的缺陷。由于该患者不仅存在PDH复合物缺陷，而且存在其他线粒体酶缺陷，且pEla和pElb基因的cDNA均无突变，因此，该患者的主要缺陷是在PDH酶蛋白向线粒体的输入系统中，在另一项研究中，我们在女性PDH缺陷症患者的PDH亚基基因中发现了一个新的18bp插入突变，线粒体细胞病变的常见原因，以及来自该专利的培养细胞中突变基因表达的广泛变化。结果表明，女性PDH缺乏症仅用酶学诊断易误诊。因此，有必要开发新的PDH缺乏症诊断方法，如DNA分析。

项目成果

Michinori Ito et al: "Molecular gsultic anrlysis of a beuale patient with pyruvate dehydugasd deficiency:Dstertinb a new wtitis and dlggenantirl expressing mutent gene prochuitin in cultusid cells" J.Inher.Metal.Dis.(in press.).

Michinori Ito 等人：“丙酮酸脱氢缺乏症 Beuale 患者的分子分析：Dstertinb 是一种新的 wtitis 和 dlggenantirl 在 cultusid 细胞中表达突变基因 prochuitin”J.Inher.Metal.Dis.（出版中）。

"Molecular genetic analysis of a female patient with pyruvate dehydrogenase deficiency : detection of a new mutation and deferential expression of mutant gene product in cultured cells." (in press).

“丙酮酸脱氢酶缺乏症女性患者的分子遗传学分析：检测培养细胞中突变基因产物的新突变和顺从表达。”

Michinori Ito et al: "Molecular genetic analysis of a female patient with pyruvate dehydrogenase deficiency:Detection of a new mutation and differentail expression of mutant gene in cultured cells" J Inher Metabol Dis. (in press).

Michinori Ito 等：“丙酮酸脱氢酶缺乏症女性患者的分子遗传学分析：培养细胞中新突变的检测和突变基因的差异表达”J Inher Metabol Dis。