中文摘要：

LRP16基因是macro domain家族成员之一,C末端含有唯一的1个保守的功能结构域.既往研究表明,该基因具有雌激素反应性,并可通过与雌激素受体α（ERα）相互作用调控其转录活性.近期我研究组发现,LRP16可与雄激素受体（AR）的共激活因子ART-27相互作用.本研究首先通过GST pull-down方法验证LRP16/ART-27/AR三者之间相互作用关系,并用免疫共沉淀实验明确了LRP16与AR存在直接的相互作用,且这种相互作用并不依赖于ART-27的存在;采用GST pull-down进一步明确LRP16与AR相互作用的结构域.结果发现,LRP16通过C端的macro domain结构域与AR的LBD域相互作用;鉴于核受体家族有较高程度的氨基酸序列保守性与功能结构域的相似性,通过GST pull-down验证了LRP16与核受体超家族成员ERβ、GR、PPARα、PPARγ的相互作用,提示LRP16至少还可与ERα以外的5个核受体家族成员相互作用;进一步采用核受体荧光素酶报告基因转染细胞,通过检测荧光素酶活性证实LRP16可增强AR、GR、ERβ、PPARα、PPARγ的转录激活活性.本研究初步证实,macro domain家族成员LRP16可与多个核受体相互作用,并增强其转录激活活性,是核受体家族的共激活因子,为进一步研究LRP16在核受体转录调控中的生理病理学功能奠定基础.

英文摘要：

LRP16 is a member of the macro domain superfamily that contains a stand alone evolutionary conserved functional module at the C-terminal region.Previous studies demonstrated that estrogen-regulated LRP16 facilitated the estrogen receptor α（ERα） and enhanced its transcriptional activity.Recently,androgen receptor（AR） coactivator ART-27 was identified to physically interact with LRP16.In this study,we tested the interactions between LRP16 and ART-27,and theirs association with AR by GST pull-down assays.A direct interaction between LRP16 and AR was discovered by immuno-coprecipitation experiments.We then used a series of GST fusions and identified that LRP16 bound to the LBD of AR via its C-terminal macro domain.As high degree of homologies existed among nuclear receptor（NR） family member,we performed GST pull-down assays to test whether LRP16 interacts with ERβ,GR,PPARα and PPARγ.The results suggested that LRP16 might interact with at least five other nuclear receptors besides ERα.The effects of LRP16 binding to those NRs were tested by the transient transfection using and dual-luciferase assays,and significant enhancement was found.Our finding suggested that LRP16 might be considered as a novel NR cofactor that enhance transcriptional activities,therefore,provided clues for further investigation in the understanding of LRP16 functions in transcription regulation.