Identification of domains mediating transcription activation, repression, and inhibition in the paired-related homeobox protein, Prx2 (S8)
Identification of domains mediating transcription activation, repression, and inhibition in the paired-related homeobox protein, Prx2 (S8)
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DOI：
10.1089/104454901750070292
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发表时间：
2001-02-01
影响因子：
3.1
通讯作者：
Kern, MJ
中科院分区：
文献类型：
--
作者：
Norris, RA;Kern, MJ
尽管有关Prx2蛋白的发育重要性的信息越来越多，但Prx2功能的结构决定因素却知之甚少。为了深入了解Prx2蛋白的转录调节区，我们产生了一系列截断突变体。Prx2反应元件(Pre)和部分tenascin启动子(Prx2的下游靶点)在瞬时转染实验中被用作报告基因。这一分析表明，在PRX1和PrX2中都发现了一个保守结构域(PRX)，激活了NIH3T3细胞的转录。这个Prx结构域以及Prx2的其他功能区都表现出细胞特异性和启动子依赖的转录调控。第二个重要的区域，OAR(干旱)结构域，在35个配对的同源结构域蛋白中保守，被观察到抑制转录。该元件的缺失导致NIH 3T3细胞中tenascin报告基因的转录增加了20倍，但在C2C12细胞中却没有。在与Gal4DNA结合域的嵌合融合中，OAR结构域在这两种细胞中都不起抑制作用，这表明它是一种抑制物，而不是抑制物。这些结果深入了解了Prx2转录因子的功能，同时建立了与PRX1的两种异构体进行比较的框架。
Despite the growing information concerning the developmental importance of the Prx2 protein, the structural determinants of Prx2 function are poorly understood. To gain insight into the transcription regulatory regions of the Prx2 protein, we generated a series of truncation mutants. Both the Prx2 response element (PRE) and a portion of the tenascin promoter, a downstream target of Prx2, were used as reporters in transient transfection assays. This analysis showed that a conserved domain (PRX), found in both Prx1 and Prx2, activated transcription in NIH 3T3 cells. This PRX domain, as well as other functional regions of Prx2, demonstrated both cell-specific and promoter-dependent transcriptional regulation. A second important region, the OAR (aristaless) domain, which is conserved among 35 Paired-type homeodomain proteins, was observed to inhibit transcription. Deletion of this element resulted in a 20-fold increase of transcription from the tenascin reporter in NIH 3T3 cells but not in C2C12 cells. The OAR domain did not function as a repressor in chimeric fusions with the Gal4 DNA binding domain in either cell type, characterizing it as an inhibitor instead of a repressor. These results give insight into the function of the Prx2 transcription factor while establishing the framework for comparison with the two isoforms of Prx1.