SEQUENCE SPECIFIC PROTEIN-BINDING TO AND ACTIVATION OF THE TGF-BETA-3 PROMOTER THROUGH A REPEATED TCCC MOTIF
SEQUENCE SPECIFIC PROTEIN-BINDING TO AND ACTIVATION OF THE TGF-BETA-3 PROMOTER THROUGH A REPEATED TCCC MOTIF
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DOI：
10.1093/nar/19.23.6419
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发表时间：
1991-12-11
影响因子：
14.9
通讯作者：
ROBERTS, A
中科院分区：
文献类型：
--
作者：
LAFYATIS, R;DENHEZ, F;ROBERTS, A
我们之前已经对 TGF-β-3 启动子进行了表征，并表明该启动子的活性在不同细胞类型中存在很大差异。虽然启动子含有一个近端 cAMP 响应元件，这对于基础和毛喉素诱导的启动子活性至关重要，但该元件并不负责启动子的可变、细胞特异性调节。在本文中，我们鉴定了 TGF-β-3 启动子近端区域的 25 个碱基对序列，该序列与一种新型 DNA 结合蛋白结合。该区域包括序列 T-CCCCTCCCTCCC (3 x TCCC)，这些 TCCC 重复序列的突变会抑制蛋白质结合。此外，我们还发现，在细胞系 A375 中，我们之前已经显示该细胞系表达高水平的 TGF-β-3 mRNA，该区域负责介导高水平的 TGF-β-3 启动子活性。紧邻 3 x TCCC 序列的 3' 是共有的 AP-2 结合位点，然而，我们表明该区域不结合 AP-2，并且 AP-2 不会反式激活 TGF-β-3 启动子。因此，我们提供了强有力的证据，表明 A375 细胞中 TGF-β-3 的高水平表达是由与启动子中重复的 TCCC 基序结合的蛋白质反式激活 TGF-β-3 启动子引起的，并表明这种 DNA 结合蛋白可能还调节该细胞因子的发育和组织特异性表达。
We have previously characterized the TGF-beta-3 promoter and shown that the activity of this promoter is highly variable in different cell types. Although the promoter contains a proximal cAMP responsive element, which is critical to basal and forskolin-induced promoter activity, this element is not responsible for the variable, cell-specific regulation of the promoter. In this paper, we identify a 25 base pair sequence in the proximal region of the TGF-beta-3 promoter that binds a novel DNA-binding protein. This region includes the sequence T-CCCTCCCTCCC, (3 x TCCC), and mutation of these TCCC repeats inhibits protein binding. Further, we show that in the cell line A375, which we have previously shown expresses high levels of TGF-beta-3 mRNA, this region is responsible for mediating high level TGF-beta-3 promoter activity. Immediately 3' to the 3 x TCCC sequence is a consensus AP-2 binding site, however, we show that this region does not bind AP-2, and AP-2 does not transactivate the TGF-beta-3 promoter. Therefore, we provide strong evidence that high level expression of TGF-beta-3 in A375 cells results from transactivation of the TGF-beta-3 promoter by a protein that binds to a repeated TCCC motif in the promoter and suggest that this DNA-binding protein likely also regulates aspects of developmental and tissue-specific expression of this cytokine