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摘要: cAMP 反应元件结合蛋白(cAMP response element-binding proteins,CREB)是一个哺乳动物转录因子家族,通过cAMP 反应元件(cAMP response element,CRE)调节cAMP和钙离子依赖性基因的表达.CREB4是CREB转录因子家族的一员.经酵母双杂交筛选人胎脑文库发现CREB4215-279aa可能与核转运因子kayopherinα2相互作用,提示karyopherinα2可能参与CREB4的跨膜转运过程.亚细胞定位结果显示,CREB4全长定位于细胞质,而缺失C端假定转膜结构域的CREB41-279aa蛋白则转移至细胞核内.荧光共定位进一步显示,CREB4和karyopherinα2共定位于细胞质中,CREB41-279aa和karyopherinα2共定位于细胞核中.结果提示C端被切除之后,CREB4被karyopherinα2转运到核内发挥转录作用.
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关键词:
- CREB4 /
- 酵母双杂交 /
- 荧光共定位 /
- kayopherinα2
Abstract: cAMP response element-binding(CREB) proteins are a family of mammalian transcription activators that mediate cAMP and calcium-dependent gene expression through the cAMP response element (CRE). CREB4 is a novel member of the human CREB family. Yeast two-hybrid system revealed that karyopherinα2 may associate with CREB4215-279aa. Subcellular location of CREB4 and CREB41-279aa showed that the GFP-CREB4 fusion protein was localized in cytoplasm, whereas the fusion protein of GFP-CREB41-279aa was translocated in nucleus. Our experiments further showed that CREB4 and karyopherinα2 were co-located in cytoplasm,but CREB41-279aa and karyopherinα2 were co-located in nucleus. These results suggested that first C-terminal was cleaved and then CREB4was carried into nucleus by karyopherinα2 to activate gene transcription.
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