摘要
鸡骨骼肌烟碱样乙酰胆碱受体 ( ACh R)γ亚基基因启动子含有几个 M- CAT元件 ,为γ亚基基因表达其全能活性所必需 .为探索 M- CAT元件结合功能特性 ,分析了 γ亚基启动子近转录起始点 - 67/ - 61位的 M- CAT元件与核因子的相互作用 .突变及结合试验证明 ,M- CAT核心序列结合几种测试组织中的核蛋白产生高迁移的 DNA-蛋白质复合物 ;侧翼序列结合肝以外的几种组织不同的核蛋白质 ,产生低迁移的 DNA-蛋白质复合物 .Southwestern印迹 ( DNA印迹 )技术在 1 3d鸡胚所有被检测的组织核抽提物中只检出了 30 k D的核蛋白 .结果提示 ,30 k D因子在多种组织普遍表达 ,可直接以单体或同质二聚体形式结合 M- CAT元件 ;而结合侧翼序列的不同组织因子结合DNA时可能需依赖普遍表达的 30 k D因子的存在 .
Several M CAT elements are present in the chicken nicotinic acetylcholine receptor γ subunit promoter and required for the totipotency of this gene.To understand the binding properties of M CAT element,the interaction of M CAT motif,at the position -67/-61 relative to the initiation site of γ promoter with nuclear proteins,were analyzed.Mutageneses and binding experiments demonstrated that the M CAT core motif bound nuclear protein(s) from tested chicken tissues to generate a high mobility complex;while the flanking sequence bound different factors to generate lower mobility complexes with the exception of liver.Southwestern blotting showed that only a 30 kD protein was expressed in tested tissues of chicken embryo at day 13. These results suggest that a 30 kD factor can directly bind to M CAT element in the manner of monomer,even homodimer and is ubiquitously expressed in tissues,while the binding of the factor(s) to flanking sequence should probably rely on the presence of a 30 kD ubiquitous factor.
出处
《中国生物化学与分子生物学报》
CSCD
2000年第5期580-585,共6页
Chinese Journal of Biochemistry and Molecular Biology
基金
This work was supported by the grant3 9770 42 2 from National Natural Science F oundation of China and thegrant972 8from Mini
关键词
M-CAT元件
结合特性
ACHR
γ亚基启动子
M CAT element,M CAT binding factor,Acetylcholine receptor γ subunit promoter
