概括
类固醇激素受体,像葡萄糖皮质体受体一样,在基因促进体中识别类似的DNA序列. 这表明共享的调节元素控制多种激素的基因表达.
科学领域:
- 分子生物学分子生物学
- 内分泌学 在内分泌学.
- 遗传学 是一个遗传学.
背景情况:
- 鼠肝中的葡萄糖皮质体受体 (GR) 与小鼠乳腺瘤病毒 (MMTV) 促进体附近的DNA序列相互作用,这对于基因转移研究中的荷尔蒙诱导至关重要.
- 在人类金属氨酸IIA基因和肉肉酶基因中发现了类似的DNA序列,这种基因对雌激素,孕激素和雄激素有反应.
研究的目的:
- 研究不同类固醇激素受体识别的DNA调节元件之间的结构相似性.
- 为了确定共享促进子序列是否调解对多种类固醇激素的基因表达反应.
主要方法:
- 基因转移实验以确定由老鼠肝脏识别的MMTV促进子序列GR.
- 微注射实验涉及删除肉酶促进剂中的特定基对.
- 使用纯化的老鼠肝GR和子子子宫孕激素受体 (PR) 进行外核酶III足迹测定.
主要成果:
- 在肉酶促进体中删除44个基对 (-208至-164) 导致了对孕激素和葡萄皮质激素依赖基因表达的协调损失.
- 纯化老鼠肝GR和子子宫PR在MMTV和肉酶的促进区域产生了类似或重叠的外核酶III足迹.
结论:
- 不同类固醇激素的调节元件可能具有结构上的相似性.
- 这些发现表明,通过共享的DNA识别序列,类固醇激素介导的基因调节具有共同的机制.
相关概念视频
Intracellular Hormone Receptors
Lipid-soluble hormones diffuse across the plasma and nuclear membrane of target cells to bind to their specific intracellular receptors. These receptors act as transcription factors that regulate gene expression and protein synthesis in the target cell
Internal Receptors
Many cellular signals are hydrophilic and therefore cannot pass through the plasma membrane. However, small or hydrophobic signaling molecules can cross the hydrophobic core of the plasma membrane and bind to internal, or intracellular, receptors that reside within the cell. Many mammalian steroid hormones use this mechanism of cell signaling, as does nitric oxide (NO) gas.
Types of Receptors: Internal Receptors
Many cellular signals are hydrophilic and cannot pass through the plasma membrane. However, small or hydrophobic signaling molecules can cross the hydrophobic core of the plasma membrane and bind intracellular receptors that reside within the cell cytoplasm or nucleus. Many mammalian steroid hormones and nitric oxide (NO) gas use this cell signaling mechanism.
Similar to membrane-bound receptors, the binding of a ligand to the intracellular receptor of causes a conformational change in the...
Similar to membrane-bound receptors, the binding of a ligand to the intracellular receptor of causes a conformational change in the...
GPCRs Regulate Adenylyl Cylase Activity
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...
Two...
Transducer Mechanism: Nuclear Receptors
Nuclear receptors, or NRs, are unique transcription factors that regulate gene transcription and affect the cellular pathways involved in reproduction, development, or metabolism. Their ability to be stimulated by small lipophilic ligands and control vital cellular processes makes them ideal drug targets. Nearly 10-15% of currently prescribed drugs target these receptors.
About 48 different soluble family members of nuclear receptors are identified that can be divided into two main classes:
About 48 different soluble family members of nuclear receptors are identified that can be divided into two main classes:
Target Cell Response to Hormones
Hormones intricately bind to receptors on the surface or within target cells, initiating a cascade of cellular responses.
Notably, the cellular response can be regulated by altering the number of receptors expressed in the cell. For example, prolonged exposure to elevated hormone levels results in a gradual decline or down-regulation in the number of receptors for that specific hormone on the cell surface. Conversely, in response to low hormone levels, cells may use up-regulation, producing an...
Notably, the cellular response can be regulated by altering the number of receptors expressed in the cell. For example, prolonged exposure to elevated hormone levels results in a gradual decline or down-regulation in the number of receptors for that specific hormone on the cell surface. Conversely, in response to low hormone levels, cells may use up-regulation, producing an...


