Transcription factors binding to the mouse HTF9 housekeeping promoter differ between cell types.
Transcription factors binding to the mouse HTF9 housekeeping promoter differ between cell types.
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与小鼠 HTF9 看家启动子结合的转录因子因细胞类型而异。
DOI：
10.1093/nar/19.16.4451
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发表时间：
1991
影响因子：
14.9
通讯作者：
P. Lavia
中科院分区：
文献类型：
--
作者：
M. P. Somma;I. Gambino;P. Lavia
小鼠CpG岛HTF9含有一个双向启动子，由两个头对头排列的看家基因共享。我们以前已经在CpG岛上发现了几个蛋白质结合元件，但在瞬时表达分析中发现起始区周围的一小段区域能够双向转录，这表明HTF9启动子的多个元件在功能上是多余的。我们现在已经比较了不同细胞类型的核提取物的结合活性。HTF9的两个蛋白结合元件与广泛分布的因子相互作用。还发现了一个潜在的强大的Sp1结合位点，然而Sp1似乎能有效地与其靶序列结合，从增殖培养的细胞中提取的提取物，而不是从成年器官制备的提取物。另一方面，一个基因(HTF9-A)上游的CCAAT盒与一个富肝因子相互作用，而不与培养的成纤维细胞提取物结合。CCAAT盒的缺失始终影响HTF9-A启动子在肝细胞培养中的瞬时表达，但不影响成纤维细胞的瞬时表达。我们的结果表明，家政启动子的普遍表达是不同类型细胞中替代元件激活的结果。
The mouse CpG island HTF9 harbours a bidirectional promoter shared by two housekeeping genes that are arranged head-to-head. We have previously identified several protein binding-elements across the CpG island, yet a short region around the initiation region was found to be capable of bidirectional transcription in transient expression assays, suggesting that the multiple elements of the HTF9 promoter are functionally redundant. We have now compared the binding activities in nuclear extracts from different cell types. Two protein-binding elements of HTF9 interact with widely distributed factors. A potentially strong Sp1 binding site was also identified, however Sp1 appeared to bind efficiently to its target sequence with extracts prepared from proliferating cultured cells, but not from adult organs. On the other hand, the CCAAT box upstream of one gene (HTF9-A) interacted with a liver-enriched factor, whereas no binding was detected with cultured fibroblasts extracts. Consistently, deletion of the CCAAT box affected transient expression from the HTF9-A promoter in hepatocyte, but not in fibroblast, cultures. Our results suggest that ubiquitous expression of housekeeping promoters results from the activation of alternative elements in different cell types.