Fenstermaker R A, Farmerie T A, Clay C M, Hamernik D L, Nilson J H
Department of Pharmacology, Western Reserve University School of Medicine, Cleveland, Ohio 44106.
Mol Endocrinol. 1990 Oct;4(10):1480-7. doi: 10.1210/mend-4-10-1480.
Expression of the glycoprotein hormone alpha-subunit gene occurs in the pituitaries of all mammals and in the placentas of primates and horses. In humans, tandem cAMP response elements (CREs), located in the proximal promoter-regulatory region of the alpha-subunit gene, act together with an adjacent upstream regulatory element to confer placenta-specific expression. Here, we report that the alpha-subunit genes of Old World Monkeys contain a single functional CRE. This suggests that tandem CREs are unique to higher primates and humans and are not absolutely required for placenta-specific expression. In contrast, the comparable promoter-regulatory region of the horse alpha-subunit gene lacks a functional CRE but appears to retain a functional upstream regulatory element. This suggests that acquisition of placenta-specific expression of the alpha-subunit gene occurred independently in these distantly related mammals. As a result, different combinations of cis-acting elements may explain why expression of the alpha-subunit gene only occurs in placenta of primates and horses.
糖蛋白激素α亚基基因在所有哺乳动物的垂体以及灵长类动物和马的胎盘中表达。在人类中，位于α亚基基因近端启动子调控区域的串联环磷酸腺苷反应元件（CREs）与相邻的上游调控元件共同作用，赋予胎盘特异性表达。在此，我们报告旧世界猴的α亚基基因包含一个单一的功能性CRE。这表明串联CREs是高等灵长类动物和人类所特有的，并非胎盘特异性表达所绝对必需的。相比之下，马α亚基基因的可比启动子调控区域缺乏功能性CRE，但似乎保留了一个功能性上游调控元件。这表明α亚基基因胎盘特异性表达的获得在这些远缘相关的哺乳动物中是独立发生的。因此，顺式作用元件的不同组合可能解释了为什么α亚基基因仅在灵长类动物和马的胎盘中表达。
