Stacey K J, Fowles L F, Colman M S, Ostrowski M C, Hume D A
Centre for Molecular and Cellular Biology, University of Queensland, Brisbane, Australia.
Mol Cell Biol. 1995 Jun;15(6):3430-41. doi: 10.1128/MCB.15.6.3430.
The mouse urokinase-type plasminogen activator (uPA) gene was used as a model macrophage colony-stimulating factor 1 (CSF-1)-inducible gene to investigate CSF-1 signalling pathways. Nuclear run-on analysis showed that induction of uPA mRNA by CSF-1 and phorbol myristate acetate (PMA) was at the transcriptional level in bone marrow-derived macrophages. CSF-1 and PMA synergized strongly in the induction of uPA mRNA, showing that at least some components of CSF-1 action are mediated independently of protein kinase C. Promoter targets of CSF-1 signalling were investigated with NIH 3T3 cells expressing the human CSF-1 receptor (c-fms). uPA mRNA was induced in these cells by treatment with CSF-1, and a PEA3/AP-1 element at -2.4 kb in the uPA promoter was involved in this response. Ets transcription factors can act through PEA3 sequences, and the involvement of Ets factors in the induction of uPA was confirmed by use of a dominant negative Ets-2 factor. Expression of the DNA binding domain of Ets-2 fused to the lacZ gene product prevented CSF-1-mediated induction of uPA mRNA in NIH 3T3 cells expressing the CSF-1 receptor. Examination of ets-2 mRNA expression in macrophages showed that it was also induced synergistically by CSF-1 and PMA. In the macrophage cell line RAW264, the uPA PEA3/AP-1 element mediated a response to both PMA and cotransfected Ets-2. uPA promoter constructs were induced 60- to 130-fold by Ets-2 expression, and the recombinant Ets-2 DNA binding domain was able to bind to the uPA PEA3/AP-1 element. This work is consistent with a proposed pathway for CSF-1 signalling involving sequential activation of fms, ras, and Ets factors.
小鼠尿激酶型纤溶酶原激活剂（uPA）基因被用作模型巨噬细胞集落刺激因子1（CSF-1）诱导型基因，以研究CSF-1信号通路。核转录分析表明，在骨髓来源的巨噬细胞中，CSF-1和佛波酯肉豆蔻酸酯（PMA）对uPA mRNA的诱导作用发生在转录水平。CSF-1和PMA在诱导uPA mRNA方面具有很强的协同作用，表明CSF-1作用的至少某些成分是独立于蛋白激酶C介导的。利用表达人CSF-1受体（c-fms）的NIH 3T3细胞研究了CSF-1信号的启动子靶点。用CSF-1处理可在这些细胞中诱导uPA mRNA，uPA启动子中-2.4 kb处的PEA3/AP-1元件参与了这一反应。Ets转录因子可通过PEA3序列发挥作用，使用显性负性Ets-2因子证实了Ets因子参与uPA的诱导。与lacZ基因产物融合的Ets-2 DNA结合结构域的表达可阻止表达CSF-1受体的NIH 3T3细胞中CSF-1介导的uPA mRNA诱导。对巨噬细胞中ets-2 mRNA表达的检测表明，它也受到CSF-1和PMA的协同诱导。在巨噬细胞系RAW264中，uPA PEA3/AP-1元件介导了对PMA和共转染的Ets-2的反应。Ets-2表达可使uPA启动子构建体诱导60至130倍，重组Ets-2 DNA结合结构域能够与uPA PEA3/AP-1元件结合。这项工作与提出的涉及fms、ras和Ets因子顺序激活的CSF-1信号通路一致。
