Baldari C T, Macchia G, Heguy A, Melli M, Telford J L
Department of Evolutionary Biology, University of Siena, Italy.
J Biol Chem. 1991 Oct 5;266(28):19103-8.
We have used an interleukin-2 (IL-2) promoter-CAT fusion gene to study activation of IL-2 gene expression by IL-1, phytohemagglutinin (PHA), phorbol myristate acetate (PMA), and calcium ionophore in the murine thymoma line EL4 and the human lymphoma line Jurkat. The two cell lines respond differently to combinations of these stimuli. IL-1 in combination with suboptimal concentration of PMA induced chloramphenicol acetyltransferase (CAT) activity in EL4. In Jurkat cells, IL-1 failed to synergize with PMA or PHA. Cotransfection with the IL-2/CAT gene and a construct capable of expressing murine T-cell type IL-1 receptors converted Jurkat cells to IL-1 responsiveness. IL-1 in combination with PHA but not with PMA resulted in induction of CAT activity in these cells. Induction of IL-2/CAT activity by all stimuli in both cell lines was blocked by the presence of EGTA in the culture medium. EGTA did not inhibit IL-1/PMA activation of an SV40 early promoter-CAT fusion gene in either EL4 or Jurkat cells; therefore, calcium was not required for IL-1 or PMA signal transduction. Jurkat cells were shown to differ from EL4 in their requirement for calcium mobilization. Two different calcium-dependent pathways of gene activation were distinguished, both of which were blocked by the immunosuppressive drug cyclosporin A.
我们利用白细胞介素-2（IL-2）启动子-CAT融合基因，研究了白细胞介素-1（IL-1）、植物血凝素（PHA）、佛波酯（PMA）和钙离子载体对小鼠胸腺瘤细胞系EL4和人淋巴瘤细胞系Jurkat中IL-2基因表达的激活作用。这两种细胞系对这些刺激组合的反应不同。IL-1与次优浓度的PMA联合使用可诱导EL4细胞中氯霉素乙酰转移酶（CAT）的活性。在Jurkat细胞中，IL-1不能与PMA或PHA协同作用。将IL-2/CAT基因与能够表达小鼠T细胞型IL-1受体的构建体共转染，可使Jurkat细胞对IL-1产生反应。在这些细胞中，IL-1与PHA联合而非与PMA联合可诱导CAT活性。两种细胞系中所有刺激对IL-2/CAT活性的诱导均被培养基中EGTA的存在所阻断。EGTA在EL4或Jurkat细胞中均不抑制SV40早期启动子-CAT融合基因的IL-1/PMA激活；因此，IL-1或PMA信号转导不需要钙离子。结果表明，Jurkat细胞在钙动员需求方面与EL4细胞不同。区分了两种不同的钙依赖性基因激活途径，这两种途径均被免疫抑制药物环孢素A阻断。
