核受体辅活化子PNRC与孤儿核受体SF1的相互作用有赖于SF1的AF-2功能结构域

Requirement of AF-2 Domain for the Interaction Between Nuclear Receptor Coactivator PNRC and Orphan Nuclear Receptor SF1

核受体辅活化子PNRC(proline richnuclearreceptorcoregulatoryprotein ,富含脯氨酸的核受体辅调节蛋白 )可通过含SH3结合模体的PNRC2 78 30 0区域与孤儿核受体类固醇生成因子 1(steroido genicfactor 1,SF1)相互作用 .激活功能 2 (activationfunction 2 ,AF 2 )结构域在核受体配体依赖性转录激活中发挥了重要作用 ,为探讨AF 2结构域在SF1转录激活中的作用机制 ,采用酵母双杂合分析、缺失突变技术和瞬时转染等研究方法考察了AF 2结构域对SF1反式激活功能及SF1与PNRC相互作用的影响 .SF1的反式激活功能有赖于AF 2结构域 ,其机制是SF1AF 2结构域的突变严重影响了SF1与PNRC的有效相互作用 ,并消除了PNRC对SF1反式激活功能的辅激活作用 .结果表明 ,SF1与PNRC的相互作用有赖于AF

Nuclear receptor coactivator PNRC (proline\|rich nuclear receptor coregulatory protein) interacts with orphan nuclear receptor SF1 (steroidogenic factor 1) through the region of PNRC 278\|320 which contains a SH3\|binding motif. The ligand\|dependent transcriptional activation involves the AF\|2 (activation function 2) domain. In order to explore the mechanism by which AF\|2 domain functions in transcriptional activation of SF1, the effects of AF\|2 domain on transactivation of SF1 and the interaction between SF1 and PNRC were examined by yeast two hybrid assay, deletion mutagenesis, cell culture and transient transfection. The results showed that deletion of AF\|2 domain of SF1 decreased the transactivation of SF1 in HeLa cells through the mechanism that the mutation of AF\|2 domain completely eliminated the interaction between SF1 and PNRC and caused substantial loss of the coactivation function of PNRC on transactivation of SF1. The results suggest that functional AF\|2 domain is necessary for the interaction between PNRC and SF1.