REGULATION OF GLUCOCORTICOID RECEPTOR FUNCTION BY CAMP

总体目标是更好地了解 糖皮质激素和激素的作用机制 通过cAMP调节淋巴的活力和生长。 两种类固醇 和环核苷酸具有抑制 免疫系统是机体对压力反应的一部分。 已知这些物质的主要转换器是一种基因- 调节受体和蛋白激酶，但立即 它们所影响的功能仅被部分理解。 证据 的交叉调节，表明cAMP有能力 促进糖皮质激素结合能力的增加， 小鼠淋巴瘤细胞系WEHI-7。 两种可能的机制是 建议：1）将受体的隐蔽池转化为 活性形式; 2）增加受体蛋白的合成。 的 将研究受体修饰与合成的关系 使用2D凝胶电泳、硫氧还蛋白测定、密度梯度 分析和分子探针用于受体蛋白的合成， 信使RNA。 在T细胞分化的某些阶段，糖皮质激素和 环核苷酸可以引发细胞溶解反应。 这种行为 为使用类固醇治疗 某些类型的白血病 细胞溶解反应也 提出了一种用于选择抗性变体的工具， 糖皮质激素受体和环腺苷酸依赖蛋白改变 激酶。 本提案涉及发现和 “第二代”类固醇/环状 核苷酸抗性变体。 发现ac初始 在小鼠淋巴瘤WEHI-7中选择对cAMP的抗性 作为一个允许的步骤，选择类固醇抗性在s 高频率 结果表明，具有 代表了新形式的类固醇耐药性，可能 包括激活糖皮质激素受体的功能， 类固醇结合状态。 这些变异细胞的特征 提出了一条线，试图确定改变的功能 这导致功能性受体的丧失。

The overall goal is to achieve a greater understanding of the mechanisms by which glucocorticoid hormones and hormones which act through cAMP regulate lymphoid viability and growth. Both steroids and cyclic nucleotide have the demonstrated capacity to suppress the immune system as a part of an organism's response to stress. The primary transducers for these agents are known to be a gene- regulating receptor and a protein kinase, but the immediate functions that they affect are only partially understood. Evidence of crossregulation is presented, showing that cAMP has the ability to promote an increase of glucocorticoid binding capacity in a murine lymphoma line, WEHI-7. Two possible mechanisms are proposed: 1) Conversion of a cryptic pool of receptors into an active form; 2) Increased synthesis of receptor protein. The involvement of receptor modification vs. synthesis will be studied using 2D-gel electrophoresis, thioredoxin assays, density gradient analysis and molecular probes for synthesis of receptor protein and messenger RNA. At certain stages of T-cell differentiation, glucocorticoids and cyclic nucleotide can elicit a cytolytic response. This behavior has provided a basis for the use of steroids in treatment of certain forms of leukemia. The cytolytic response has also presented a tool for selection of resistant variants containing altered glucocorticoid receptors and cyclic AMP-dependent protein kinase. This proposal deals with the discovery and characterization of a "second generation" of steroid/cyclic nucleotide resistant variants. It was found that ac initial selection for resistance to cAMP in the murine lymphoma WEHI-7 acts as a permissive step towards selection of steroid resistance at s high frequency. The results indicate that the variants which have been obtained represent new forms of steroid resistance, possibly involving functions that activate the glucocorticoid receptor into a steroid binding state. Characterization of these variant cell lines is proposed in an attempt to identify the altered functions which lead to the loss of functional receptor.