Hayes T E, Kitchen A M, Cochran B H
Proc Natl Acad Sci U S A. 1987 Mar;84(5):1272-6. doi: 10.1073/pnas.84.5.1272.
The c-fos gene is rapidly and transiently activated in quiescent BALB/c-3T3 cells in response to serum, platelet-derived growth factor or conditioned medium from v-sis-transformed cells. This activation occurs at the level of transcription and in the absence of new protein synthesis. Using a gel electrophoresis DNA-binding assay, we have found a DNA-binding activity in BALB/c-3T3 cells that is induced within 20 min of treatment with conditioned medium from v-sis-transformed cells. A DNA methylation interference assay has shown that this factor binds to a sequence approximately 346 base pairs upstream of the transcription initiation site of the human c-fos gene. Insulin, epidermal growth factor, and phorbol 12-myristate 13-acetate fail to induce this DNA-binding factor. Protein synthesis inhibitors do not block the induction of this activity. We propose that this factor preexists in an inactive form in quiescent cells and that its binding activity is activated in response to appropriate extracellular inducers.
c-fos基因在静止的BALB/c-3T3细胞中会因血清、血小板衍生生长因子或来自v-sis转化细胞的条件培养基而迅速且短暂地被激活。这种激活发生在转录水平，且无需新的蛋白质合成。通过凝胶电泳DNA结合分析，我们在BALB/c-3T3细胞中发现了一种DNA结合活性，在用来自v-sis转化细胞的条件培养基处理20分钟内即可被诱导。DNA甲基化干扰分析表明，该因子结合于人c-fos基因转录起始位点上游约346个碱基对的序列。胰岛素、表皮生长因子和佛波酯12-肉豆蔻酸酯13-乙酸酯无法诱导这种DNA结合因子。蛋白质合成抑制剂不会阻断这种活性的诱导。我们提出，该因子在静止细胞中以无活性形式预先存在，并且其结合活性会因适当的细胞外诱导剂而被激活。
