Dey A, Nebert D W, Ozato K
Laboratory of Developmental and Molecular Immunity, National Institute of Child Health and Human Development, Bethesda, MD 20892.
DNA Cell Biol. 1991 Sep;10(7):537-44. doi: 10.1089/dna.1991.10.537.
The c-fos proto-oncogene is inducible by cAMP, phorbol esters, serum, and growth factors. The induction by cAMP is mediated by the conserved cAMP response element (CRE), while induction by phorbol esters, serum, and growth factors requires a distal element called the serum response element (SRE). In addition to these elements, a consensus AP-1 transcription factor binding site is located next to SRE. Upstream regions of the mouse and human c-fos genes were footprinted in vivo by the ligation-mediated polymerase chain (PCR). Our results show that all three elements are constitutively protected in mouse liver and lung and in cultured human A431 cells. No major change in the protection profile was detected in A431 cells following stimulation with epidermal growth factor or in mice at birth, when c-fos is known to be induced. These results suggest that the inducible cis elements of the c-fos gene are poised, ready to respond immediately to external signals.
原癌基因c-fos可被环磷酸腺苷（cAMP）、佛波酯、血清和生长因子诱导。cAMP的诱导作用由保守的环磷酸腺苷反应元件（CRE）介导，而佛波酯、血清和生长因子的诱导作用则需要一个称为血清反应元件（SRE）的远端元件。除了这些元件外，一个共有AP-1转录因子结合位点位于SRE旁边。通过连接介导的聚合酶链反应（PCR）对小鼠和人类c-fos基因的上游区域进行了体内足迹分析。我们的结果表明，这三个元件在小鼠肝脏和肺以及培养的人类A431细胞中均受到组成型保护。在用表皮生长因子刺激后，A431细胞中未检测到保护图谱的重大变化；在已知c-fos被诱导的出生时的小鼠中也未检测到。这些结果表明，c-fos基因的可诱导顺式元件处于准备状态，随时准备对外部信号立即做出反应。
