KERATINOCYTES--MODULATION BY RETINOIC ACID

类维A酸类化合物是一类有效的治疗药物。 一些皮肤病。为了提高治疗水平 这些疾病，有必要阐明其发病机制 类维甲酸，如全反式维甲酸(RA)，发挥其抗 增殖效应。因此，这些研究的长期目标是， 以确定RA如何抑制角质形成细胞的生长。……的重要行动 RA是角质形成细胞，是抑制鸟氨酸脱羧酶(OD)的一种酶 其产物多胺是细胞生长所必需的。它是 因此提出了确定抑制ODC基因表达是否是一种 视黄醇作用的直接后果以及这种抑制是如何实施的。 这些实验旨在测试RA抑制ODC的假设 基因转录通过视黄酸受体(RAR)介导的机制。这 将通过(1)确定RA和/或放线菌亚胺的效果进行检查 用Run-On方法研究人ODC基因的相对转录速率 转录；(2)确定在角质形成细胞中表达哪些RAR和 区分细胞RA结合蛋白的作用和 通过使用嵌合的RAR/雌激素而产生的α、β和伽马受体 将被导入角质形成细胞的受体；(3)识别顺式- 与反式作用因子相互作用导致类风湿关节炎的作用DNA元件- 利用体外足迹，介导ODC基因转录的变化， 凝胶滞留试验和连接到细胞的分离元件的转染素 胸苷激酶-β-珠蛋白基因；(4)编码非核糖核酸的cDNA的分离 与RA作用有关的RAR反式作用因子。澄清： RA抑制ODC基因表达的机制将导致 关于维甲酸如何发挥其抗增殖作用的重要信息 效果。

Retinoids are a class of compounds which are potent therapeutic agents for a number of dermatological diseases. In order to improve treatment of these diseases, it is necessary to elucidate the mechanism whereby retinoids, such as all-trans-retinoic acid (RA), exert their anti- proliferative effects. The long term goal of these studies is, therefore, to determine how RA inhibits keratinocyte growth. An important action of RA is keratinocytes is to inhibit ornithine decarboxylase (OD), an enzyme whose products, the polyamines, are necessary for cell growth. It is therefore proposed to determine if inhibition of ODC gene expression is a direct consequence of retinoid action and how this repression is exerted. These experiments re designed to test the hypothesis that RA suppresses ODC gene transcription through a RA receptor (RAR)-mediated mechanism. This will be examined by (1) determining the effects of RA and/or cycloheximide on the relative transcription rates of the human ODC gene using run-on transcription; (2) determining which RAR is expressed in keratinocytes and discriminating between the actions of the cellular RA binding protein and the alpha-, beta-, and gamma-RARs through the use of chimeric RAR/estrogen receptors that will be transfected into keratinocytes; (3) identifying cis- acting DNA elements that interact with trans-acting factors to cause RA- mediated changes in ODC gene transcription, using in vitro footprinting, gel retardation assays, and transfectin of isolated elements ligated to the thymidine kinase-beta-globin gene; and (4) isolation of cDNAs encoding non- RAR trans-acting factors which are implicated in RA action. Elucidation of the mechanisms whereby RA suppresses ODC gene expression will yield important information on how retinoids exert their anti-proliferative effects.