IDENTIFICATION OF 2 POLYPEPTIDE SEGMENTS OF CCAAT ENHANCER-BINDING PROTEIN REQUIRED FOR TRANSCRIPTIONAL ACTIVATION OF THE SERUM-ALBUMIN GENE
IDENTIFICATION OF 2 POLYPEPTIDE SEGMENTS OF CCAAT ENHANCER-BINDING PROTEIN REQUIRED FOR TRANSCRIPTIONAL ACTIVATION OF THE SERUM-ALBUMIN GENE
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DOI：
10.1101/gad.4.8.1416
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发表时间：
1990-08-01
影响因子：
10.5
通讯作者：
MCKNIGHT, SL
中科院分区：
文献类型：
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作者：
FRIEDMAN, AD;MCKNIGHT, SL
我们使用分子遗传学方法产生系统改变形式的CCAAT/增强子结合蛋白（C/EBP）。我们的实验的目的是确定区域的C/EBP，有助于其激活的能力，从血清白蛋白基因在培养的肝癌细胞的启动子转录。早期的实验表明，DNA结合结构域必须保持完整，C/EBP才能激活白蛋白转录。我们现在提供了C/EBP基因激活作用所需的两个额外元素的证据。一个这样的元件出现在位于蛋白质的氨基末端附近的28个残基区域内。另一个映射到蛋白质的更广泛，更内部的区域，似乎表现出功能冗余。这些新定义的C/EBP元件表现出在其他基因调控蛋白的研究中描绘的“激活”结构域的两个特征。首先，它们在C/EBP与其DNA底物结合的能力中没有明显的作用。其次，它们在附加到不同蛋白质的DNA结合结构域上后保留功能。这两种假定的激活元件的特征都不是在电荷或任何特定氨基酸的优势上有明显的区别。然而，更氨基末端的元件确实表现出几个特征，表明它可能呈现α-氨基末端。螺旋结构这些研究提供的意见和试剂，将是有价值的，为未来的研究有关的生理功能的C/EBP。
We used molecular genetic methods to generate systematically altered forms of CCAAT/enhancer-binding protein (C/EBP). The aim of our experiments was to identify regions of C/EBP that contribute to its capacity to activate transcription from the promoter of the serum albumin gene in cultured hepatoma cells. Earlier experiments had shown that the DNA-binding domain must remain intact for C/EBP to activate albumin transcription. We now provide evidence of two additional elements of C/EBP that are required for its gene-activating role. One such element occurs within a 28-residue region located close to the amino terminus of the protein. The other maps to a broader, more internal region of the protein and appears to exhibit functional redundancy. These newly defined elements of C/EBP exhibit two characteristics of "activation" domains delineated in studies of other gene regulatory proteins. First, they play no obvious role in the capacity of C/EBP to bind to its DNA substrate. Second, they retain function after being appended onto the DNA-binding domain of a different protein. Neither of these putative activating elements is characterized by overt distinction in either charge or preponderance of any particular amino acid. The more amino-terminal element does, however, exhibit several features suggesting that it may assume an .alpha.-helical structure. These studies offer observations and reagents that will be valuable for future studies concerning the physiologic function of C/EBP.