TYPE II 3BETA HSD GENE REGULATION OF DHEAS SYNTHESIS

DHEAS 合成的 II 型 3BETA HSD 基因调控

• 批准号: 2053797
• 负责人: PETER J HORNSBY
• 金额: $ 15.23万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-30 至 1998-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2053797
• 关键词: DNA binding protein; DNA footprinting; adrenal glands; aging; animal genetic material tag; animal tissue; dehydroepiandrosterone; developmental genetics; gel mobility shift assay; gene expression; genetic regulation; genetic regulatory element; genetic transcription; human fetus tissue; human genetic material tag; human tissue; life cycle; molecular cloning; nuclear runoff assay; nucleic acid sequence; polymerase chain reaction; species difference; steroid delta isomerase; steroid hormone biosynthesis; tissue /cell culture

Dehydroepiandrosterone and its sulfate (DHEA(S)) show a cycle of large changes in secretion from the adrenal cortex over the life span in humans. The secretion of these steroids is very high in the fetus, low in childhood, high again in young adulthood, followed by a progressive age- related decline. Dependent on age, 40-100% of local tissue androgens and estrogens in both men and women are derived from DHEAS. The critical regulatory point in the biosynthesis of DHEAS is 3beta- hydroxysteroid/delta4 '5-isomerase (3beta-HSD). The low level of activity of this enzyme in the human adrenal cortex, but not in animal glands such as that of the cow, limits the flux of pregnenolone to A steroids, such as cortisol, and maintains the synthesis of delta5 steroids, principally DHEA(S). The proposed experiments will analyze the differences between the type Il human 3beta-HSD gene, which is expressed in the adrenal cortex and other steroidogenic tissues, and the 3beta-HSD gene expressed in the bovine adrenal. Transcription rates and mRNA stability will be assessed as possible causes of the differences in 3beta-HSD expression between the bovine and human adrenal cortex, and between the different zones of the human adrenal cortex. The bovine 3beta-HSD gene (or genes) expressed in the adrenal cortex will be isolated, its structure analyzed, and the tissue distribution of its transcript determined. The difference in expression levels between the human type Il and the bovine gene will be tested using reporter constructs from the two genes transfected into primary human and bovine adrenal cells. The elements in the type II human and the bovine 3beta-HSD genes responsible for tissue-specific expression and second messenger regulation, and nuclear proteins from the adrenal cortex that bind to these elements, will be characterized. The possible identity of such proteins to known transcription factors will be tested. Cell culture experiments will examine whether the cycle of DHEAS synthesis over the life span in humans results from intrinsic changes in expression of 3beta-HSD. The abundance in adrenocortical tissue of nuclear proteins that bind to the regulatory elements of the type II 3beta-HSD gene will be correlated with the cycle. These experiments will elucidate the molecular basis for the regulation of the human 3beta-HSD type II gene and thereby the regulation of DHEAS synthesis. This information will provide a basis for understanding the significance of the unique secretion of this hormone in humans and the significance of its age-related decline for aging and age-related diseases.

脱氢表雄酮及其硫酸盐（S））显示了一个大的循环 人类寿命中肾上腺皮质的分泌变化。 这些类固醇的分泌在胎儿中很高，低 童年，成年后再次高，随后是渐进的年龄 - 相关下降。 依赖年龄，40-100％的局部组织雄激素和 男性和女人的雌激素均来自DHEAS。 DHEAS生物合成的关键调节点是3beta- 羟基固醇/delta4'5-异构酶（3Beta-HSD）。 低水平的活动 人类肾上腺皮质中的这种酶，但在动物腺中没有这种酶 就像牛的那样，将妊娠的通量限制为类固醇，例如 皮质醇并维持Delta5类固醇的合成，主要是 DHEA（S）。 提出的实验将分析 IL型人类3Beta-HSD基因，该基因在肾上腺皮质和 其他类固醇组织和牛中表达的3Beta-HSD基因 肾上腺。 将作为可能的原因评估转录率和mRNA稳定性 牛与人之间3Beta-HSD表达的差异 肾上腺皮质，在人肾上腺的不同区域之间 皮质。 在肾上腺中表达的牛3Beta-HSD基因（或基因） 皮层将分离，分析其结构，并组织 确定其笔录的分布。 表达的差异 人类类型IL和牛基因之间的水平将使用 来自转染到原代人的两个基因的记者构造和 牛肾上腺细胞。 II型人和牛的元素 3Beta-HSD基因负责组织特异性表达和第二 Messenger调节和来自肾上腺皮质的核蛋白 与这些元素结合，将被表征。 可能的身份 将测试此类已知转录因子的蛋白质。 细胞培养 实验将检查生命中DHEAS合成的周期 人类的跨度是由3Beta-HSD表达的内在变化引起的。 核蛋白的肾上腺皮质组织的丰度，与 II型3Beta-HSD基因的调节元素将与 周期。 这些实验将阐明调节的分子基础 人类3Beta-HSD类型 II基因，从而调节DHEAS合成。 此信息 将为理解独特的意义提供基础 这种激素在人类中的分泌及其与年龄相关的重要性 衰老和与年龄有关的疾病的下降。