2 DISTINCT ESTROGEN-REGULATED PROMOTERS GENERATE TRANSCRIPTS ENCODING THE 2 FUNCTIONALLY DIFFERENT HUMAN PROGESTERONE-RECEPTOR FORM-A AND FORM-B
2 DISTINCT ESTROGEN-REGULATED PROMOTERS GENERATE TRANSCRIPTS ENCODING THE 2 FUNCTIONALLY DIFFERENT HUMAN PROGESTERONE-RECEPTOR FORM-A AND FORM-B
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DOI：
10.1002/j.1460-2075.1990.tb08280.x
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发表时间：
1990-05-01
期刊：
影响因子：
11.4
通讯作者：
CHAMBON, P
中科院分区：
文献类型：
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作者：
KASTNER, P;KRUST, A;CHAMBON, P
从T47D乳腺癌细胞中合成的人孕激素受体（hPR） cDNA及其5‘’侧区进行克隆和测序。与其他PR同源物的比较证实了核受体的模块化结构特征。与鸡的同源物一样，有两种hPR形式，A和B，分别起源于AUG2（密码子165）和AUG1的翻译起始。利用各种cDNA衍生探针对T47D mRNA进行Northern blot分析，鉴定出两类hPR mRNA，一类可以编码hPR形式B，另一类缺乏AUG1上游的5”区域。S1核酸酶定位和引物延伸分析证实，第二类hPR转录本在+737和+842之间启动，因此编码hPR形式A，而不是形式b。通过使用hPR基因5''-侧翼序列作为嵌合基因的启动子区域，我们发现一个功能性启动子（位于-711和+31之间）指导hPR mrna从位于+1和+15的真实起始位点启动。最重要的是，嵌合基因的转录起始证明了在+464和+1105之间存在第二个启动子。用表达人雌激素受体的载体进行瞬时共转染实验表明，虽然在相应的序列中没有检测到经典的雌激素应答元件，但这两个启动子都是雌激素诱导的。当瞬时表达时，两种形式的hPR相似地激活了含有单个回文黄体酮应答元件（PRE）的报告基因的转录，而形式B更有效地激活了小鼠乳腺肿瘤病毒长末端重复序列的PRE。然而，卵白蛋白启动子的转录被hPR形式A诱导，而不是形式B。
The human progesterone receptor (hPR) cDNA, synthesized from T47D breast cancer cells, and the hPR gene 5''-flanking region were cloned and sequenced. Comparison of the cDNA-deduced amino acid sequence with other PR homologues demonstrated the modular structure characteristic of nuclear receptors. As in the case of the chicken homologue, there are two hPR forms, A and B, which originate from translational initiation at AUG2 (codon 165) and AUG1, respectively. Northern blot analysis of T47D mRNA using various cDNA derived probes identified two classes of hPR mRNAs, one of which could code for hPR form B, while the other one lacked the 5'' region upstream of AUG1. S1 nuclease mapping and primer extension analyses confirmed that the second class of hPR transcripts are initiated between +737 and +842 and thus encode hPR form A, but not form B. By using the hPR gene 5''-flanking sequences as promoter region in chimeric genes, we show that a functional promoter (located between -711 and +31) directs initiation of hPR mRNAs from the authentic start sites located at +1 and +15. Most importantly, initiation of transcription from chimeric genes demonstrated the existence of a second promoter located between +464 and +1105. Transient co-transfection experiments with vectors expressing the human estrogen receptor showed that both promoters were estrogen inducible, although no classical estrogen responsive element was detected in the corresponding sequences. When transiently expressed, the two hPR forms similarly activated transcription from reporter genes containing a single palindromic progestin responsive element (PRE), while form B was more efficient at activating the PRE of the mouse mammary tumor virus long terminal repeat. Transcription from the ovalbumin promoter, however, was induced by hPR form A, but not by form B.