SF-1 INDEPENDENT TRANSCRIPTIONAL REGULATION OF P450SCC

描述（由申请人提供） 胆固醇侧链裂解酶，细胞色素P450 SCC，启动 所有类固醇激素的生物合成，是限速的， 规范的步骤。许多研究表明，P450 SCC基因转录在细胞内的表达与细胞凋亡密切相关。 肾上腺和性腺基本相同，并依赖于孤儿核 受体SF-1，但P450 SCC基因在胎盘中的转录 使用与肾上腺和性腺中使用的顺式作用元件不同的顺式作用元件， 并且不依赖于SF-1。P450 SCC在人胎盘JEG-3细胞中的表达 以cAMP反应的方式，这与P450 SCC的调节非常相似， 在细胞滋养层细胞的原代培养物中，但SF-1无法通过 JEG-3细胞中的RT-PCR。之前在米勒医生那里工作过吗的实验室已经表明， 胎盘特异性因子参与转录调控， P450 SCC在胎盘中表达，但未发现这些因素。我最近的工作 米勒医生的身体吗的实验室已经导致了新的LBP转录的克隆 因子：LBP-1b和LBP-9，通过这些因子调节P450 SCC的转录。 胎盘特异性成分LBP-1b，与其他几个成员相似 这个新描述的LBP转录因子家族，似乎诱导 P450 SCC的胎盘转录。相比之下，LBP-9是全新的， 似乎抑制P450 SCC的胎盘转录; LBP-9于2001年2月报告。这些LBP蛋白的发现， 与P450 SCC启动子的-155/-131区域的相互作用允许我提出 以下具体目标： 目的1：表征LBP-1b和LBP-9。 a）确定LBP-9是否具有阻遏结构域或激活结构域， 域 B）分析LBP-1b-EGFP和LBP-9-EGFP是否竞争结合至 P450 SCC的-155/-131元件。 c）确定LBP-1b和LBP-9是否相互影响？s转录 活性使用我们最近构建的稳定细胞系。 目的2：阐明基因表达的组织特异性和个体发生性模式， LBP相关蛋白 目的3：鉴定可能促进P450 SCC反式激活的辅助因子 LBP-1b或LBP-9基因。这些目标的实现将为 有关SF-1非依赖性胎盘转录性质的信息 人P450 SCC基因。

DESCRIPTION (provided by applicant) The cholesterol side-chain cleavage enzyme, cytochrome P450scc, initiates the biosynthesis of all steroid hormones and is the rate-limiting and hormonally regulated step. Many studies have shown that P450scc gene transcription in the adrenal and gonad are essentially identical, and depend on the orphan nuclear receptor SF-1, but the transcription of the P450scc gene in the placenta employs cis-acting elements different from those used in the adrenal and gonad, and is independent of SF-1. P450scc is expressed in human placental JEG-3 cells in a cAMP-responsive fashion that is very similar to the regulation of P450scc in primary cultures of cytotrophoblast cells, but SF-1 is not detectable by RT-PCR in JEG-3 cells. Previous work in Dr. Miller?s laboratory has shown that placental-specific factors are involved in the transcriptional regulation of P450scc in the placenta, but these factors were not identified. My recent work in Dr. Miller?s laboratory has lead to the cloning of novel LBP transcription factors: LBP-1b and LBP-9, that regulate P450scc transcription through these placental-specific elements. LBP-1b, which is similar to several other members of this newly-described family of LBP transcription factors, appears to induce the placental transcription of P450scc. By contrast LBP-9 is wholly novel and appears to repress placental transcription of P450scc; a mouse homologue of LBP-9 was reported in February 2001. The discovery of these LBP proteins that interact with the-155/-131 region of the P450scc promoter permits me to propose the following Specific Aims: Aim 1: Characterize LBP-1b and LBP-9. a) Determine whether LBP-9 possesses a repression domain or an activation domain. b) Analyze whether LBP-1b-EGFP and LBP-9-EGFP compete for binding to the-155/-131 element of P450scc. c) Determine whether LBP-1b and LBP-9 affect each other?s transcriptional activity using our recently constructed stable cell lines. Aim 2: Delineate the tissue-specific and ontogenic expression patterns of LBP-related proteins. Aim 3: Identify co-factors that may facilitate the transactivation of P450scc gene by LBP-1b or by LBP-9. Completion of these aims will provide new information about the nature of SF-1-independent placental transcription of the human P450scc gene.