Posttranscriptional regulation of the human prolactin gene in IM-9-P3 cells by retinoic acid.
Posttranscriptional regulation of the human prolactin gene in IM-9-P3 cells by retinoic acid.
复制标题
视黄酸对 IM-9-P3 细胞中人催乳素基因的转录后调节。
作者：
B. Gellersen;R. Kempf;S. Hartung;A. Bonhoff;G. DiMattia
IM-9-P3 细胞系家族源自 B 淋巴母细胞 IM-9 细胞系，利用蜕膜型启动子转录人 PRL (hPRL) 基因，并为研究控制 hPRL 基因垂体外表达的因素提供了模型。在这里，我们描述了视黄酸 (RA) 对 IM-9-P3 家族成员中 hPRL 基因表达的调节。当细胞在补充有经过葡聚糖包被木炭处理的胎牛血清的培养基中培养时，添加 RA 会导致低 hPRL 生产克隆 IM-9-P31 和中度生产克隆 IM-9-P32 的 hPRL 分泌增加 2 倍（ED50 分别为 0.53 和 0.13 nM），但在高 hPRL 生产 IM-9-P33 中则不然。 克隆。 RA 反应细胞系的分泌物在暴露的前 24 小时内稳定增加，并在几天内保持较高水平。 hPRL mRNA 稳态水平的伴随增加并不是由于核连续实验评估的 hPRL 基因转录增强，而是由于信息稳定。在 RA 处理的 IM-9-P32 细胞中，hPRL mRNA 的半衰期从 9 小时显着延长至 22 小时。发现转录物优先与膜结合的多核糖体相关，因此可用于分泌途径。当我们研究 RA 信号的潜在转导子（即 RA 受体亚型 hRAR α、-β 和 -γ 以及细胞 RA 结合蛋白）的表达时，我们没有在 hPRL 阴性克隆 IM-9-P6 或 hPRL 阳性克隆 IM-9-P31、IM-9-P32 中检测到 hRAR γ 或细胞 RA 结合蛋白转录本。 和 IM-9-P33。 hRAR α 在所有细胞系中均等表达且不受 RA 调节，而 hRAR β 则差异表达并受 RA 控制。这种受体亚型在 IM-9-P 家族的 hPRL 阴性成员中不存在，在 RA 反应性 IM-9-P31 和 IM-9-P32 细胞系中通过快速转录上调被 RA 强烈诱导，而在 RA 抗性 IM-9-P33 细胞系中仅轻微诱导，表明 RA 在介导 hPRL 基因表达的作用中发挥作用。
The IM-9-P3 family of cell lines, which are derived from the B-lymphoblastoid IM-9 cell line, transcribe the human PRL (hPRL) gene by utilization of the decidual-type promoter and provide a model to study factors controlling extrapituitary expression of the hPRL gene. Here we describe regulation of hPRL gene expression in members of the IM-9-P3 family by retinoic acid (RA). When cells were incubated in medium supplemented with fetal calf serum that had been treated with dextran-coated charcoal, the addition of RA caused a 2-fold stimulation of hPRL secretion in the low hPRL-producing clone IM-9-P31 and the moderate producer IM-9-P32 (ED50, 0.53 and 0.13 nM, respectively), but not in the high hPRL-producing IM-9-P33 clone. Secretion from the RA-responsive cell lines increased steadily over the first 24 h of exposure and remained elevated for several days. The concomitant increase in hPRL mRNA steady state levels was not due to enhanced transcription of the hPRL gene, as assessed by nuclear run-on experiments, but, rather, to message stabilization. In RA-treated IM-9-P32 cells, the half-life of hPRL mRNA was significantly increased from 9 to 22 h. The transcripts were found to be preferentially associated with membrane-bound polysomes, thus being available for the secretory pathway. When we studied the expression of potential transducers of the RA signal, namely the RA receptor subtypes hRAR alpha, -beta, and -gamma and cellular RA-binding protein, we did not detect hRAR gamma or cellular RA-binding protein transcripts in the hPRL-negative clone IM-9-P6 or the hPRL-positive clones IM-9-P31, IM-9-P32, and IM-9-P33. hRAR alpha was equally expressed in all cell lines and not regulated by RA, whereas hRAR beta was differentially expressed and controlled by RA. This receptor subtype was absent from hPRL-negative members of the IM-9-P family, strongly induced by RA in the RA-responsive IM-9-P31 and IM-9-P32 cell lines via rapid transcriptional up-regulation, and only slightly induced in the RA-resistant IM-9-P33 cell line, suggesting a function in mediation of the effect of RA on hPRL gene expression.