CAMP-DEPENDENT TRANSCRIPTIONAL REGULATION OF CYP51

P.I.和外国合作者合作研究的长期目标是确定CYP51(羊毛甾醇14α-去甲基酶细胞色素P450)高水平表达在单倍体减数分裂后生殖细胞中的作用。FIRCA的这项建议解决了这一总体目标的一部分，并将导致理解体细胞和生殖细胞中cAMP依赖的CYP51转录所涉及的生化机制。建议的三年的具体目标是研究细胞色素P51在类固醇生成(体细胞)细胞(目标1)和单倍体生殖细胞(目标2)中依赖cAMP的转录调控。母基金(DK28350)解决了肾上腺皮质中依赖ACTH(CAMP)的基因(特别是编码P450酶)的转录，这是维持最佳类固醇生成能力所必需的过程。AIM 1是DK28350的延伸，它将确定肾上腺皮质中是否存在编码类固醇生成P450(胆固醇代谢)和CYP51(胆固醇生物合成)的基因的cAMP依赖转录之间的联系。似乎有两条不同的信号通路--氧固醇/SRE和cAMP/CRE相互作用，控制类固醇生成细胞中的细胞色素P51水平。初步数据表明，在单倍体生殖细胞中，CYP51在转录水平上受cAMP调控。AIM 2是DK28350研究的新方向，将为这种减数分裂后转录调控奠定生物化学基础。这些研究的结果将提供对类固醇激素生物合成的更详细的了解，类固醇激素生物合成是男性生殖中胆固醇代谢和精子发生的主要途径。

The long term goal of collaborative research between the P.I. and the foreign collaborator is to determine the role of the high level expression of CYP51 (lanosterol 14alpha-demethylase cytochrome P450) in haploid, postmeiotic germ cells. This FIRCA proposal addresses a portion of this overall goal and will lead to an understanding of the biochemical mechanisms involved in cAMP-dependent transcription of CYP51 in somatic and germ cells. The specific aims for the proposed three years are to study cAMP- dependent transcriptional regulation of CYP51 in steroidogenic (somatic) cells (Aim 1) and in haploid germ cells (Aim 2). The parent grant (DK28350) addresses ACTH (cAMP)-dependent transcription of genes (particularly encoding P450 enzymes) in the adrenal cortex, a process essential for maintenance of optimal steroidogenic capacity. Aim 1 is an extension of DK28350 and will establish whether a link between cAMP-dependent transcription of genes encoding steroidogenic P450s (cholesterol metabolism) and CYP51 (cholesterol biosynthesis) exists in the adrenal cortex. It seems likely that two different signalling pathways, oxysterol/SRE and cAMP/CRE, interact to control CYP51 levels in steroidogenic cells. Preliminary data indicates that CYP51 is transcriptionally regulated by cAMP in haploid germ cells. Aim 2 is a new direction for studies in DK28350 and will establish the biochemical basis of this postmeiotic transcriptional regulation. Results from these studies will provide a more detailed understanding of steroid hormone biosynthesis which is a major path of cholesterol metabolism and of spermatogenesis in male reproduction.