Boulanger Marie-Chloé, Liang Chen, Russell Rodney S, Lin Rongtuan, Bedford Mark T, Wainberg Mark A, Richard Stéphane
Terry Fox Molecular Oncology Group, Lady Davis Institute, Sir Mortimer B. Davis Jewish General Hospital, Montréal, Québec, Canada.
J Virol. 2005 Jan;79(1):124-31. doi: 10.1128/JVI.79.1.124-131.2005.
The human immunodeficiency virus (HIV) transactivator protein, Tat, stimulates transcription from the viral long terminal repeats via an arginine-rich transactivating domain. Since arginines are often known to be methylated, we investigated whether HIV type 1 (HIV-1) Tat was a substrate for known protein arginine methyltransferases (PRMTs). Here we identify Tat as a substrate for the arginine methyltransferase, PRMT6. Tat is specifically associated with and methylated by PRMT6 within cells. Overexpression of wild-type PRMT6, but not a methylase-inactive PRMT6 mutant, decreased Tat transactivation of an HIV-1 long terminal repeat luciferase reporter plasmid in a dose-dependent manner. Knocking down PRMT6 consistently increased HIV-1 production in HEK293T cells and also led to increased viral infectiousness as shown in multinuclear activation of a galactosidase indicator assays. Our study demonstrates that arginine methylation of Tat negatively regulates its transactivation activity and that PRMT6 acts as a restriction factor for HIV replication.
人类免疫缺陷病毒（HIV）反式激活蛋白Tat通过富含精氨酸的反式激活结构域刺激病毒长末端重复序列的转录。由于精氨酸通常已知会被甲基化，我们研究了1型HIV（HIV-1）Tat是否是已知蛋白精氨酸甲基转移酶（PRMT）的底物。在此我们确定Tat是精氨酸甲基转移酶PRMT6的底物。Tat在细胞内与PRMT6特异性结合并被其甲基化。野生型PRMT6而非甲基化无活性的PRMT6突变体的过表达，以剂量依赖的方式降低了HIV-1长末端重复荧光素酶报告质粒的Tat反式激活。敲低PRMT6持续增加HEK293T细胞中HIV-1的产生，并且如半乳糖苷酶指示剂测定的多核激活所示，还导致病毒感染性增加。我们的研究表明，Tat的精氨酸甲基化负向调节其反式激活活性，并且PRMT6作为HIV复制的限制因子发挥作用。
