Antonson Per, Al-Beidh Farah, Matthews Jason, Gustafsson Jan-Ake
Department of Biosciences at Novum, Karolinska Institutet, Novum, S-14157 Huddinge, Sweden.
Gene. 2004 Mar 3;327(2):233-8. doi: 10.1016/j.gene.2003.11.022.
Ligand-induced gene activation by nuclear receptors involves the recruitment of coactivators to hormone bound receptors. Recent results have shown that RAP250, also termed as ASC-2/PRIP/TRBP/NRC/AIB3, plays a critical role as a coactivator of nuclear receptors. In this study, we have determined the genomic organization of the human RAP250 gene in order to identify the promoter region. By searching the GenBank database for EST sequences, we could identify two previously unknown exons in the 5'-end of the gene. Our results show that the RAP250 gene consists of 15 exons spanning 111 kb. All sequences of the splice donor and acceptor sites fit the GT-AG role for splicing. We also show using linkage analysis that the mouse Rap250 gene is located on chromosome 2 close to the agouti gene. The RAP250 promoter is GC-rich and TATA-less, and contains multiple Sp1 binding sites and a MYC binding site. A reporter plasmid containing the 5' flanking region of the RAP250 gene showed significant activity compared to pGL3-basic and minimal thymidine kinase (TK) reporter plasmids in transfection experiments using luciferase reporter genes. Our data show that the RAP250 has a complex genomic structure with a promoter that is regulated by multiple transcription factors for its basal expression.
核受体介导的配体诱导基因激活涉及共激活因子招募至激素结合受体。最近的研究结果表明，RAP250，也被称为ASC-2/PRIP/TRBP/NRC/AIB3，作为核受体的共激活因子发挥关键作用。在本研究中，我们确定了人类RAP250基因的基因组结构以识别启动子区域。通过在GenBank数据库中搜索EST序列，我们在该基因的5'端鉴定出两个先前未知的外显子。我们的结果表明，RAP250基因由15个外显子组成，跨度为111 kb。剪接供体和受体位点的所有序列均符合GT-AG剪接规则。我们还通过连锁分析表明，小鼠Rap250基因位于2号染色体上，靠近刺鼠基因。RAP250启动子富含GC且无TATA盒，包含多个Sp1结合位点和一个MYC结合位点。在使用荧光素酶报告基因的转染实验中，与pGL3-basic和最小胸苷激酶（TK）报告质粒相比，含有RAP250基因5'侧翼区域的报告质粒显示出显著活性。我们的数据表明，RAP250具有复杂的基因组结构，其启动子受多种转录因子调控以实现基础表达。
