Bevilacqua M A, Faniello M C, Cimino F, Costanzo F
Dipartimento di Biochimica e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Italy.
Biochem Biophys Res Commun. 1997 Nov 7;240(1):179-82. doi: 10.1006/bbrc.1997.7632.
The transcription of the human H ferritin gene is regulated by a transcription factor, called Bbf, which binds an enhancer element located in the -100/+1 region of the H promoter. To evaluate a possible role of Bbf phosphorylation on the promoter efficiency, we exposed HeLa cells to the phosphatase inhibitor okadaic acid (OA). The okadaic acid treatment increased about 4-fold the transcription driven by the -100/+1 region of the H promoter. However, the DNA binding activity of Bbf was not modified by OA, as assessed by EMSA. Immunoprecipitation experiments demonstrated that the OA-treatment stimulates and/or stabilizes the complex between Bbf and the nuclear protein p300, most probably by inducing the phosphorylation state of the complex. Bbf depends on the p300 molecule to trigger RNA polymerase II and thus transcription of the H ferritin gene.
人类H铁蛋白基因的转录受一种名为Bbf的转录因子调控，该因子与位于H启动子-100/+1区域的增强子元件结合。为了评估Bbf磷酸化对启动子效率的可能作用，我们将HeLa细胞暴露于磷酸酶抑制剂冈田酸（OA）中。冈田酸处理使H启动子-100/+1区域驱动的转录增加了约4倍。然而，如通过电泳迁移率变动分析（EMSA）所评估的，Bbf的DNA结合活性并未被OA改变。免疫沉淀实验表明，OA处理很可能通过诱导复合物的磷酸化状态来刺激和/或稳定Bbf与核蛋白p300之间的复合物。Bbf依赖p300分子来触发RNA聚合酶II，从而启动H铁蛋白基因的转录。
