Human immunodeficiency virus type 1 Vpr interacts with spliceosomal protein SAP145 to mediate cellular pre-mRNA splicing inhibition
Human immunodeficiency virus type 1 Vpr interacts with spliceosomal protein SAP145 to mediate cellular pre-mRNA splicing inhibition
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DOI：
10.1016/j.micinf.2007.01.013
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发表时间：
2007-04-01
影响因子：
5.8
通讯作者：
Aida, Yoko
中科院分区：
文献类型：
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作者：
Hashizume, Chieko;Kuramitsu, Madoka;Aida, Yoko
Vpr是人类免疫缺陷病毒1型（HIV-1）的辅助基因产物，通过介导长末端重复序列激活、细胞周期停滞在G2期和凋亡来影响病毒和细胞增殖。我们以前发现，Vpr在体内和体外都起着调节前mRNA剪接的新作用。然而，Vpr的细胞靶点以及Vpr抑制细胞前mRNA剪接的机制尚不清楚。在这里，我们清楚地表明，Vpr抑制细胞前体mRNA的剪接，如β-珠蛋白前体mRNA和免疫球蛋白（1g）M前体mRNA，第三个α-螺旋结构域和富含精氨酸的区域是重要的，其抑制剪接的能力。此外，使用在Vpr的两个结构域中具有特异性取代的突变体，我们证明Vpr和SAP 145之间的相互作用是剪接抑制所不可或缺的。最后，免疫共沉淀和体外竞争性结合试验表明Vpr与SAP 145缔合并干扰SAP 145-SAP 49复合物的形成。因此，这些结果表明Vpr的细胞表达可能通过干扰宿主细胞中SAP 145-SAP 49复合物的功能来阻断剪接体组装。(c)2007年，Elsevier Masson SAS。All rights reserved.
Vpr, an accessory gene product of human immunodeficiency virus type 1 (HIV-1), affects both viral and cellular proliferation by mediating long terminal repeat activation, cell cycle arrest at the G2 phase, and apoptosis. We previously found that Vpr plays a novel role as a regulator of pre-mRNA splicing both in vivo and in vitro. However, the cellular target of Vpr, as well as the mechanism of cellular pre-mRNA splicing inhibition by Vpr, is unknown. Here, we show clearly that Vpr inhibits the splicing of cellular pre-mRNA, such as ss-globin pre-mRNA and immunoglobulin (1g) M pre-mRNA and that the third alpha-helical domain and arginine-rich region are important its ability to inhibit splicing. Additionally, using mutants with specific substitutions in two domains of Vpr, we demonstrated that the interaction between Vpr and SAP145, an essential splicing factor, was indispensable for splicing inhibition. Finally, co-immunoprecipitation and in vitro competitive binding assays indicated that Vpr associates with SAP145 and interferes with SAP145-SAP49 complex formation. Thus, these results suggest that cellular expression of Vpr may block spliceosome assembly by interfering with the function of the SAP145-SAP49 complex in host cells. (c) 2007 Elsevier Masson SAS. All rights reserved.