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Coupled Expression of The Genes Encoding The Constituents of The Glycine Cleavage System in Chicken

编码甘氨酸裂解系统成分的基因在鸡中的耦合表达

基本信息

批准号：
62570101
负责人：
HIRAGA Koichi
金额：
$ 1.34万
依托单位：
Toyama Medical and Pharmaceutical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62570101/
关键词：
coupled expression of the genes glycine decarboxylase cDNA H-protein cDNA glycine cleavage system 遺伝子の臓器特異的発現調節 H-蛋白cDNA 鶏ゲノムDNAライブラリーグリシン脱炭酸酵素遺伝子 H-蛋白遺伝子高グリシン血症

项目摘要

several clones of cDNA encoding qlycine decarboxylase, a constituent of the glycine cleavage system, were isolated from chicken liver cDNA expression libraries with a specific antibody. The overlapping cDNA clones evenly coded in an identical and open reading frame for the partial primary structures of the enzyme, and sequence of the 3,490 base long glycine decarboxylse cDNA was determined. H-protein cDNA was also cloned by immunoscreening, and this encoded the precursor from of chicken h-protein of 164 amino acid residues within the 840 base long cDNA sequence. Using both cDNA fragments we could analyze the mode of expression of the glycine decarboxylase and h-protein genes.Glycine decarboxylase mRNA aboundance varied in parallel with the content of the enzyme system in liver, kidney, and brain, which reveal specific activities of the overall reaction at a tatio of 35:11:1. in contrast, heart, spleen, and skeletal muscle mitochondria inactive in the reaction contained significant but small amounts of active H-protein and its mRNAs, whereas glycine decarboxylase and its mRNA were not found, indicationg that tissue-specific distribution of the enzyme system is primarily determined by expression of the hlycine decarboxylase gene. We defined them as the basal expression of the H-protein gene. Excluding the basal expression, relative efficiencies of run-off transcription on the glycine decarboxylase and H-protein genes appeared to be equal and the equimolar level of glycine decarboxylase and H-protein mRNAs are maintaianed in liver, kidney, and brain, irrespective of the difference in the amounts of expression of the genes. It is suggested that the magnitude of the glycine cleavage activity is specified by the coordinate mechanism which resides in regulation for biosynthesis of the components of the glycine cleavage system, except that the glycine decarboxylase gene expression alone is repressed in the cells of mesenchymal origin.

用一种特异性抗体从鸡肝脏表达文库中克隆了甘氨酸裂解系统中的甘氨酸脱羧酶的编码基因。确定了该酶部分一级结构的完全相同的开放阅读框中的重叠克隆，并测定了3,490碱基长的甘氨酸脱羧酶的序列。用免疫筛选法克隆了鸡H蛋白基因，编码鸡H蛋白的前体蛋白，编码840个碱基长的序列中164个氨基酸残基。利用这两个片段可以分析甘氨酸脱羧酶和H蛋白基因的表达方式。甘氨酸脱羧酶基因的丰度与肝、肾和脑中酶系统的含量平行变化，显示出整个反应的比活性为35：11：1。相反，在反应中不活跃的心脏、脾和骨骼肌线粒体含有显著但少量的活性H蛋白及其mRNAs，而没有发现甘氨酸脱羧酶及其mRNA，这表明酶系统的组织特异性分布主要由甘氨酸脱羧酶基因的表达决定。我们将其定义为H蛋白基因的基础表达。除去基础表达，甘氨酸脱羧酶和H蛋白基因的径流转录的相对效率似乎是相等的，甘氨酸脱羧酶和H蛋白的mRNAs在肝、肾和脑中保持等摩尔水平，而与基因的表达量的差异无关。我们认为，甘氨酸裂解活性的大小是由甘氨酸裂解系统各组成部分的生物合成调节机制决定的，除了甘氨酸脱羧酶基因的表达在间充质来源的细胞中受到抑制之外。