PAP-1, the mutated gene underlying the RP9 form of dominant retinitis pigmentosa, is a splicing factor
PAP-1, the mutated gene underlying the RP9 form of dominant retinitis pigmentosa, is a splicing factor
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DOI：
10.1016/j.yexcr.2004.07.029
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发表时间：
2004-11-01
影响因子：
3.7
通讯作者：
Iguchi-Ariga, SMM
中科院分区：
文献类型：
--
作者：
Maita, H;Kitaura, H;Iguchi-Ariga, SMM
PAP-1是Pim-1癌基因的体外磷酸化靶标。尽管PAP-1与Pim-1结合，但它不是Pim-1在体内磷酸化的底物。PAP-1是一种常染色体显性遗传性视网膜色素变性（adRP）RP 9的缺陷基因。然而，RP 9是一种罕见的疾病，只有两个错义突变已被描述，所以PAP-1和RP 9之间的联系的报告是试探性的。PAP-1的确切细胞作用在当时也是未知的。我们现在报告，PAP-1定位于核斑点包含剪接因子SC 35和直接与另一个剪接因子，U2 AF 35相互作用。此外，我们使用体外和体内剪接测定来显示PAP-1具有改变前mRNA剪接模式的活性，并且该活性依赖于PAP-1的磷酸化状态。我们使用相同的剪接试验来检测RP 9患者中发现的两种PAP-1突变形式的活性。结果显示，虽然其中一个突变H137 L与野生型PAP-1相比对剪接活性没有影响，但另一个突变D170 G导致剪接活性缺陷和磷酸化PAP-1比例降低。因此，D170 G突变可能通过减少PAP-1磷酸化改变视网膜基因的剪接而引起RP。这些结果表明，PAP-1在前mRNA剪接中具有作用，并且考虑到其他三种剪接因子与adRP有关，这一发现提供了令人信服的进一步证据，证明PAP-1确实是RP 9基因。(C)2004年爱思唯尔公司All rights reserved.
PAP-1 is an in vitro phosphorylation target of the Pim-1 oncogene. Although PAP-1 binds to Pim-1, it is not a substrate for phosphorylation by Pim-1 in vivo. PAP-1 has recently been implicated as the defective gene in RP9, one type of autosomal dominant retinitis pigmentosa (adRP). However, RP9 is a rare disease and only two missense mutations have been described, so the report of a link between PAP-1 and RP9 was tentative. The precise cellular role of PAP-1 was also unknown at that time. We now report that PAP-1 localizes in nuclear speckles containing the splicing factor SC35 and interacts directly with another splicing factor, U2AF35. Furthermore, we used in vitro and in vivo splicing assays to show that PAP-1 has an activity, which alters the pattern of pre-mRNA splicing and that this activity is dependent on the phosphorylation state of PAP-1. We used the same splicing assay to examine the activities of two mutant forms of PAP-1 found in RP9 patients. The results showed that while one of the mutations, H137L, had no effect on splicing activity compared with that of wild-type PAP-1, the other, D170G, resulted in both a defect in splicing activity and a decreased proportion of phosphorylated PAP-1. The D170G mutation may therefore cause RP by altering splicing of retinal genes through a decrease in PAP-1 phosphorylation. These results demonstrate that PAP-1 has a role in pre-mRNA splicing and, given that three other splicing factors have been implicated in adRP, this finding provides compelling further evidence that PAP-1 is indeed the RP9 gene. (C) 2004 Elsevier Inc. All rights reserved.