DIFFERENT COMPOSITE REGULATORY ELEMENTS DIRECT EXPRESSION OF THE HUMAN ALPHA-SUBUNIT GENE TO PITUITARY AND PLACENTA
DIFFERENT COMPOSITE REGULATORY ELEMENTS DIRECT EXPRESSION OF THE HUMAN ALPHA-SUBUNIT GENE TO PITUITARY AND PLACENTA
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DOI：
10.1074/jbc.270.44.26497
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发表时间：
1995-11-03
影响因子：
4.8
通讯作者：
NILSON, JH
中科院分区：
文献类型：
--
作者：
HECKERT, LL;SCHULTZ, K;NILSON, JH
为了鉴定细胞特异性表达所必需的人α亚基基因的元件，我们产生了一系列跨越启动子近端区域的大约400个碱基对（bp）的阻断突变，并在垂体中使用瞬时转染分析来检测它们。（α T3）和胎盘（BeWo）细胞系，两种细胞类型中启动子活性的比较揭示了垂体和胎盘中转录所需的共同和独特元件，两个强元件，环AMP反应元件（CRE）和上游调节元件（URE）调节BeWo细胞中α亚基基因的表达。相反，α T3细胞中的启动子活性需要一系列较弱的元件，这些元件包括克雷斯、URE以及两个先前描述的元件，垂体糖蛋白激素基础元件（PGBE）和促性腺激素特异性元件（GSE），以及两个新的元件，我们命名为α基础元件1和α基础元件2（α BE 1和α BE 2）。这些新元件位于-316和-302 bp之间（α BE 1）和-296和-285 bp Southwestern印迹分析显示，α BE 1特异性结合54-和56-kDa蛋白，其他研究揭示了结合CRE的蛋白质与占据PGBE、α BE 1和α BE 2的蛋白质之间的几种潜在相互作用，这表明促性腺激素特异性表达是通过一种独特的复合调节元件发生的，该元件包括胎盘特异性增强子的成分。
To identify elements of the human alpha subunit gene necessary for cell-specific expression, we generated an array of block mutations spanning approximately 400 base pairs (bp) of promoter proximal region and examined them using transient transfection analysis in pituitary (alpha T3) and placental (BeWo) cell lines, Comparison of promoter activity in the two cell types revealed both common and unique elements required for transcription in pituitary and placenta, Two strong elements, the cyclic AMP response element (CRE) and the upstream regulatory element (URE), regulate expression of the a subunit gene in BeWo cells, In contrast, promoter activity in alpha T3 cells requires an array of weaker elements, These include the CREs, the URE, as well as two previously described elements, pituitary glycoprotein hormore basal element (PGBE) and gonadotrope-specific element (GSE), and two new elements we designated as the a basal elements 1 and 2 (alpha BE1 and alpha BE2). These new elements reside between -316 and -302 bp (alpha BE1) and -296 and -285 bp (alpha BE2) of the human a subunit promoter and bind distinct proteins designated alpha BP1 and alpha BP2, respectively, Southwestern blot analysis revealed that alpha BE1 specifically binds 54- and 56-kDa proteins, Additional studies disclosed several potential interactions between proteins that bind the CRE and proteins that occupy PGBE, alpha BE1, and alpha BE2, suggesting that gonadotrope-specific expression occurs through a unique composite regulatory element that includes components of the placenta-specific enhancer.