Tsytsykova A V, Tsitsikov E N, Geha R S
Division of Immunology, Children's Hospital and Departments of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.
J Biol Chem. 1996 Feb 16;271(7):3763-70. doi: 10.1074/jbc.271.7.3763.
Four nuclear factor of activated T cells (NF-AT) binding motifs were found in the murine CD40 ligand promoter. Electrophoretic mobility shift assays using 18-base pair (bp) long oligonucleotides corresponding to the proximal site and nuclear extracts from activated T cells revealed two complexes which were inhibited by cyclosporin A and contained NF-ATc and NF-ATp. Neither complex contained AP-1 proteins. Multimers of the 18-bp oligonucleotides were not active in transient transfection assays using luciferase reporter gene constructs. In contrast, a 30-bp long oligonucleotide bound AP-1 proteins in addition to NF-AT proteins and its multimers strongly induced luciferase gene expression. These results suggested that NF-AT proteins play an important role in the expression of the CD40L gene and that their transcriptional activity requires AP-1 binding.
在小鼠CD40配体启动子中发现了四个活化T细胞核因子（NF-AT）结合基序。使用对应于近端位点的18个碱基对（bp）长的寡核苷酸和活化T细胞的核提取物进行的电泳迁移率变动分析显示出两种复合物，它们被环孢菌素A抑制，并包含NF-ATc和NF-ATp。两种复合物均不包含AP-1蛋白。18-bp寡核苷酸的多聚体在使用荧光素酶报告基因构建体的瞬时转染试验中无活性。相反，一个30-bp长的寡核苷酸除了结合NF-AT蛋白外还结合AP-1蛋白，并且其多聚体强烈诱导荧光素酶基因表达。这些结果表明，NF-AT蛋白在CD40L基因的表达中起重要作用，并且它们的转录活性需要AP-1结合。
