c‐fos transcriptional activation and repression correlate temporally with the phosphorylation status of TCF.

摘要: EGF-induction of human astrocytoma and A431 cells leads to c-fos transcriptional activation then repression. This could be correlated with changes in the DNA binding characteristics regulatory protein ternary complex factor (TCF) present nuclear extracts from these cells. Band shifts showed appearance induction-related slowly migrating protein-DNA complexes, detected as complexes on SRE using a truncated SRF molecule by direct Drosophila E74 Ets-protein recognition sequence. By several criteria both types represented TCF. The slow activation, their disappearance coincided ensuing shut-off. Blocking repression phosphatase inhibitor okadaic acid led continued presence. They were sensitive 2A but not 1 alpha, similar formed partially purified p62TCF phosphorylated copurifying kinase activity. Thus phosphorylation state TCF strongly promoter Since formation mediated full-sized was only slightly affected under comparable conditions, we propose model for regulation involving modification constitutively bound