Analysis of the components of a novel coactivator.the NF complex, and its regulatory mechanisms

核因子复合体(NF45-NF90和NF45-NF110)的转录活性受c-fos基因上游增强子和核心启动子区域的调控。在小鼠细胞中敲除内源性NF90/NF110导致c-fos转录在血清刺激下的诱导减弱。染色质免疫沉淀分析表明，血清诱导前后，核因子复合体占据了c-fos增强子/启动子区，血清诱导后，它们在c-fos基因编码区的占有率与RNAPII的占有率平行增加。因此，核因子复合体似乎是多功能的共激活因子，协调基因表达的不同步骤，促进可诱导基因的快速反应。

The transcriptional activities of the NF complexes (NF45-NF90 and NF45-NF110) are mediated by both the upstream enhancer and core promoter regions of the c-fos gene. Knockdown of the endogenous NF90/NF110 in mouse cells results in a diminished induction of c-fos transcription upon serum stimulation. Chromatin immunoprecipitation assays show that the NF complexes occupy the c-fos enhancer/promoter region before and after serum induction and that their occupancies within the coding region of the c-fos gene increase in parallel to that of RNAPII upon serum induction. Thus, the NF complexes appear to serve as multifunctional coactivators that coordinate different steps of gene expression to facilitate rapid response of inducible genes.