AROMATASE CYTOCHROME-P450 IN RAT OVARIAN GRANULOSA-CELLS BEFORE AND AFTER LUTEINIZATION - ADENOSINE 3',5'-MONOPHOSPHATE-DEPENDENT AND INDEPENDENT REGULATION - CLONING AND SEQUENCING OF RAT AROMATASE CDNA AND 5' GENOMIC DNA
AROMATASE CYTOCHROME-P450 IN RAT OVARIAN GRANULOSA-CELLS BEFORE AND AFTER LUTEINIZATION - ADENOSINE 3',5'-MONOPHOSPHATE-DEPENDENT AND INDEPENDENT REGULATION - CLONING AND SEQUENCING OF RAT AROMATASE CDNA AND 5' GENOMIC DNA
复制标题
DOI：
10.1210/mend-4-1-3
复制
发表时间：
1990-01-01
影响因子：
--
通讯作者：
RICHARDS, JS
中科院分区：
文献类型：
--
作者：
HICKEY, GJ;KRASNOW, JS;RICHARDS, JS
大鼠卵巢芳香化酶细胞色素P450(P450arom)的完整核苷酸序列是从三个大鼠颗粒/黄体细胞的cDNA文库中分离得到的。合成的P450arom基因全长1597个碱基，编码508个氨基酸的蛋白质(计算摩尔质量分数为58,263)，并与大鼠卵巢组织中3个转录产物(3.3、2.6和1.9kb)杂交。从大鼠基因组文库中分离到一个5‘’端的基因组片段，该片段含有外显子1和538个碱基对的5‘端侧翼序列，其中包括可能的启动子元件。此外，在排卵前卵泡的颗粒细胞中，P450arom mRNA和雌二醇(E)的生物合成受到cAMP依赖的机制的调节，但在促黄体生成/hCG诱导的黄体化后，P450arom mRNA和雌二醇(E)的生物合成受到cAMP不依赖的机制的维持。PO颗粒细胞向黄体细胞(PO+hCG)表型的转变需要在体内暴露hCG 5h。一旦黄体细胞表型被编程，在没有激素或增加细胞内cAMP的药物的情况下，P450arom mRNA和E的生物合成在黄体细胞中以结构性的方式保持长达10天。此外，分离PO+hCG(7h)的卵泡，在获取颗粒细胞之前，用可逆转录抑制剂(放线菌素-D)或翻译(放线菌素-D)孵育1-3h，对颗粒细胞的形态和功能黄体化都没有影响。因此，颗粒细胞在排卵后5-7小时内发生快速的细胞和分子事件，这改变了芳香酶基因的激素调节。
The complete nucleotide sequence for rat ovarian aromatase cytochrome P450 (P450arom) has been derived from four cDNA clones isolated from three rat granulosa/luteal cell .lambda.gt11 cDNA expression libraries. The composite P450arom cDNA extends 1597 basepairs, encodes a protein of 508 amino acids (calculated mol wt = 58,263), and hybridizes to three mRNA transcripts (3.3, 2.6, and 1.9 kilobases in size) in rat ovarian tissues. A 5'' genomic fragment was isolated from a rat genomic library and shown to contain exon 1 and 538 basepairs of 5'' flanking sequences, including putative promoter elements. Further, we document that P450arom mRNA and estradiol (E) biosynthesis are regulated by cAMP-dependent mechanisms in granulosa cells of preovulatory (PO) follicles, but are maintained by cAMP-independent mechanisms after LH/hCG-induced luteinization. The transition of the PO granulosa cell to the luteal cell (PO + hCG) phenotype requires 5 h of exposure to hCG in vivo. Once the luteal cell phenotype is programed, P450arom mRNA and E biosynthesis are maintained in the luteinized cells for up to 10 days in a constitutive manner in the absence of hormones or agents that increase intracellular cAMP. Furthermore, when PO + hCG (7 h) follicles were isolated and incubated for 1-3 h with reversible inhibitors of transcription (actinomycin-D) or translation (cycloheximide) before harvesting the granulosa cells, neither morphological nor functional luteinization of granulosa cells in culture was impaired. Thus, rapid cellular and molecular events occur in granulosa cells within 5-7 h after an ovulatory LH/hCG surge that alter the hormonal regulation of the aromatase gene.