FINE-STRUCTURE MAPPING OF THE 3 MOUSE ALPHA-FETOPROTEIN GENE ENHANCERS
FINE-STRUCTURE MAPPING OF THE 3 MOUSE ALPHA-FETOPROTEIN GENE ENHANCERS
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DOI：
10.1128/mcb.8.3.1169
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发表时间：
1988-03-01
影响因子：
5.3
通讯作者：
TILGHMAN, SM
中科院分区：
文献类型：
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作者：
GODBOUT, R;INGRAM, RS;TILGHMAN, SM
先前已经在小鼠α-SMA的5“-侧翼区中鉴定了多个细胞增强子。瞬时表达法检测甲胎蛋白基因。在本报告中，增强子已定位于转录起始位点上游DNA的2.5、5.0和6.5个碱基处的三个区域，长度为200至300个碱基对。三个增强子的核苷酸序列分析揭示了它们之间的同源性，其中最显着的是10和18个核苷酸长度的两个区域。两个增强子进行了详细分析，并显示出由多个不相同的结构域组成，其中没有一个是足够的完整的增强子活性;相反，它们在产生增强子的完整活性中以相加的方式起作用。通过比较肝脏和非肝脏来源的细胞系中的亚结构域的活性来评估增强子在~ 2.5个酶处的组织特异性活性，发现这是增强子内的阳性元件和其5“端的至少一个阴性元件的结果。相比之下，当单独测试最小必需区域时，增强子在约5.0千碱基处的组织特异性得以维持。核苷酸序列的相似性，以及增强子之间的差异，可以解释它们在组织培养和体内的不同生物活性。
Multiple cellular enhancers have been identified previously in the 5''-flanking region of the mouse .alpha.-fetoprotein gene by transient expression assay. In this report the enhancers have been localized to three regions 200 to 300 base pairs in length at 2.5, 5.0, and 6.5 kilobases of DNA upstream of the transcriptional start site. Nucleotide sequence analysis of the three enhancers revealed areas of homology among them, the most significant of which were two regions of 10 and 18 nucleotides in length. Two of the enhancers were analyzed in detail and shown to be composed of multiple nonidentical domains, none of which was sufficient for full enhancer activity; rather, they acted in an additive fashion in generating the full activity of the enhancer. The tissue-specific activity of the enhancer at -2.5 kilobases was assessed by comparing the activities of subdomains in liver- and non-liver-derived cell lines and was found to be the result of both positive elements within the enhancer and at least one negative element to its 5'' end. In contrast, the tissue specificity of the enhancer at -5.0 kilbases was maintained when the minimal essential region was tested alone. The nucleotide sequence similarities, as well as the differences among the enhancers, may explain their differing biological activities both in tissue culture and in vivo.