HEPATIC GLUTAMINASE

肝谷氨酰胺酶

• 批准号: 3236140
• 负责人: MALCOLM WATFORD
• 金额: $ 3.4万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-07-01 至 1990-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3236140
• 关键词: antibody; cell differentiation; chimeric proteins; chromatin; complementary DNA; drug related diabetes mellitus; enzyme induction /repression; gene expression; genetic transcription; glutaminase; growth /development; hepatocellular carcinoma; immunochemistry; in situ hybridization; isozymes; kidney metabolism; laboratory rat; liver cells; liver metabolism; messenger RNA; nucleic acid sequence; phosphates; protein engineering; protein sequence; tissue /cell culture

Glutamine plays an important biosynthetic role in all mammalian cells. Glutamine is used by the liver during diabetes, the kidney during metabolic acidosis and the mammary gland during lactation, it is also a major respiratory fuel for many rapidly dividing cells including cancer cells. The major enzymes of glutamine catabolism in mammalian tissues are two isozymes of phosphate activated glutaminase. The liver type is found exclusively in adult liver while the other enzyme (kidney-type) is found in all other glutamine utilizing tissues, including fetal liver and hepatoma cells. The aim of the work described is to characterize and understand the role and regulation of phosphate activated glutaminase in rat liver. This work stems from the observation that hepatic glutaminase activity is increased 4-fold during streptozotocin diabetes. The enzyme has been purified, specific antibodies raised against it and used to identify a putative cDNA. The identify of the cDNA will be confirmed by comparison of the DNA and amino acid sequences, hybrid selection of mRNA and analysis of fusion peptide. The cDNA will be used to determine the relative abundance of mRNA and the rate of transcription hepatic glutaminase gene in liver from control and diabetic rats. Extracellular stimuli involved in the regulation of hepatic glutaminase gene expression will be identified using isolated hepatocytes and hepatoma cells. The cDNA will be used to identify genomic sequences encoding liver-type glutaminase and other glutamine utilizing enzymes. The distribution of liver- and kidney-type glutaminase (activity, protein and mRNA) will be determined in different hepatoma cells and in rat liver at different stages of development. Chromatin structure will be analyzed in cells showing differential expression of the two genes. These systems offer a unique model for the study of tissue-specific, hormonal and developmental regulation of glutaminase gene expression. The results will provide valuable insights into why there are two enzymes and what their functions are in the different cell types.

谷氨酰胺在所有哺乳动物细胞中起重要的生物合成作用。 谷氨酰胺在糖尿病期间由肝脏使用 代谢性酸中毒和乳腺乳腺，也是一个 许多快速分裂的细胞（包括癌症）的主要呼吸燃料 细胞。 哺乳动物组织中谷氨酰胺分解代谢的主要酶 是磷酸激活的两个同工酶。 肝脏类型是 仅在成年肝脏中发现，而其他酶（肾脏类型）为 在所有其他利用组织的谷氨酰胺中发现，包括胎儿肝和 肝癌细胞。 所描述的工作的目的是表征和 了解磷酸盐激活的谷氨酰胺酶的作用和调节 大鼠肝脏。 这项工作源于观察到肝谷氨酰胺酶活性是 在链蛋白酶糖尿病期间增加了4倍。 酶已经 纯化的，具有针对它的特定抗体，用于识别 推定的cDNA。 cDNA的识别将通过比较确认 DNA和氨基酸序列的杂种选择mRNA和 融合肽的分析。 cDNA将用于确定 mRNA的相对丰度和转录率 对照和糖尿病大鼠肝脏中的谷氨酰胺酶基因。 细胞外 参与肝谷氨酰胺酶基因表达的刺激 将使用分离的肝细胞和肝癌细胞来鉴定。 该cDNA将用于识别编码肝型的基因组序列 谷氨酰胺酶和其他利用酶的谷氨酰胺。 分布 肝脏和肾脏型谷氨酰胺酶（活性，蛋白质和mRNA）将是 在不同的肝癌细胞和大鼠肝脏中确定 发展阶段。 染色质结构将在细胞中分析 显示两个基因的差异表达。 这些系统提供了 研究组织特异性，荷尔蒙和发育的独特模型 调节谷氨酰胺酶基因表达。 结果将提供 关于为什么有两种酶及其功能的宝贵见解 在不同的细胞类型中。