中文摘要：

目的：研究新克隆的激活素受体相互作用蛋白3（ActRIP3）的免疫学特性和其介导Ser／Thr激酶型受体胞内信号传导的作用。方法：以酵母双杂交法发现的ActRIP基因片段作为探针，从小鼠脑cDNA文库中克隆ActRIP3基因。EIA法分析其与激活素ⅡA型受体（ActRⅡA）结合能力，Westernblot杂交检测成熟蛋白在组织中的表达，免疫组化染色分析其在脑组织中的分布，采用pcDNA-AetRIP3与CAGA-1ux报告基因质粒共转染HEK293细胞分析信号传导作用。结果：克隆的ActRIP3基因全长1197bp，编码101个氨基酸残基，EIA分析显示ActRIP3与ActRⅡA具有特异性结合作用，这种作用与ActRIP3的N末端氨基酸序列有关。Westernblot杂交显示天然ActRIP3相对分子质量约为14000，在多种组织表达，免疫组化染色显示其在脑组织中的分布以海马及下丘脑为主。通过表达ActRIP3可促进激活索诱导的特异性基因转录活性。结论：ActRIP3属于ActRIP家族新成员，具有特异结合ActRⅡA的能力，并具有促进激活素信号传导的作用。

英文摘要：

Objective：To investigate the immunological characterization of a novel activin receptor-interacting protein 3 （ActRIP3） and intracellular signal transduction of serine/threonine kinase receptors mediated by it. Methods：The ActRIP3 gene from a mouse brain cDNA library was cloned by using fragment of ActPdP screened by Yeast Two-hybrid as the probe. Its abihty to combine with type Ⅱ activin receptor（ActRⅡA） was analyzed by EIA, expression of mature ActRIP3 protein was detected in tissues by Western blot, and its localization in brain was analyzed by immunohistochemistry. Its signal function was analyzed by co-transfecting pcDNA- ActRIP3 and CAGA-lux into HEK293 cells. Results：The cloned full-length cDNA for ActRIP3 is 1 197 bp, encoding 101 amino acids. The specific EIA analysis revealed that ActRIP3 could specifically combine with ActRⅡA, which has a relationship with N-terminal sequence of ActRIP3. Western blot revealed that the molecular weight of native ActRIF3 is about 14 000, and ActRIP3 expressed in many tissues. The immunohistochemistry showed that its distribution in brain is mainly in hippocampus and hypothalamus. Over expressed ActRIP3 promoted the transcription activity of specific genes induced by activin. Conclusion：ActRIP3 is a novel member of ActRIP family, which has the ability to specifically combine with ActRⅡA and promote activin signaling transduction.