Sandri-Goldin R M, Hibbard M K
Department of Microbiology and Molecular Genetics, College of Medicine, University of California, Irvine 92717-4025, USA.
J Virol. 1996 Jan;70(1):108-18. doi: 10.1128/JVI.70.1.108-118.1996.
The herpes simplex virus type 1 (HSV-1) immediate-early regulatory protein ICP27 is required for the inhibition of host cell splicing during viral infection and for the reorganization of antigens associated with the small nuclear ribonucleoprotein particles (snRNPs). To determine what effect ICP27 had on splicing proteins that might cause their redistribution, we looked at proteins that were immunoprecipitated with anti-Sm antisera. No significant changes were seen in the migration or amounts of several snRNP common and snRNP-specific proteins from infected cells labeled with [35S]methionine, suggesting that the synthesis of these proteins was not altered by viral infection. However, when cells were labeled with 32Pi, differences were seen in the phosphorylation of at least two proteins depending on whether ICP27 was expressed. One protein, which had an apparent molecular mass of about 85 kDa, was highly phosphorylated during wild-type HSV-1 infection but much less so during infection with an ICP27 null mutant. The other protein, which migrated at the position of the U1 70-kDa protein and was precipitated with U1-specific antiserum, was also more highly phosphorylated when ICP27 was expressed during infection. Furthermore, a phosphoprotein with an apparent molecular mass of 63 kDa was found to coimmunoprecipitate with anti-Sm antisera during wild-type HSV-1 infection. ICP27 has an apparent molecular mass of 63 kDa, and immunoblot analysis confirmed that ICP27 coimmunoprecipitated with snRNPs. Analysis of mutations throughout the ICP27 protein demonstrated that the region that was required for this interaction was the C terminus of the protein, which includes a cysteine-histidine-rich region that resembles a zinc-finger-like motif. These data suggest that ICP27 interacts with snRNPs during infection and that it fosters changes in the phosphorylation state of at least two proteins that immunoprecipitate with snRNPs, although these studies do not demonstrate whether it does so directly or indirectly.
单纯疱疹病毒1型（HSV-1）的立即早期调节蛋白ICP27是病毒感染期间抑制宿主细胞剪接以及与小核核糖核蛋白颗粒（snRNP）相关抗原重组所必需的。为了确定ICP27对可能导致其重新分布的剪接蛋白有何影响，我们研究了用抗Sm抗血清免疫沉淀的蛋白。在用[35S]甲硫氨酸标记的感染细胞中，几种snRNP共同蛋白和snRNP特异性蛋白的迁移或数量没有明显变化，这表明这些蛋白的合成没有因病毒感染而改变。然而，当细胞用32Pi标记时，根据ICP27是否表达，至少两种蛋白的磷酸化存在差异。一种表观分子量约为85 kDa的蛋白，在野生型HSV-1感染期间高度磷酸化，但在ICP27缺失突变体感染期间磷酸化程度低得多。另一种在U1 70-kDa蛋白位置迁移并与U1特异性抗血清沉淀的蛋白，在感染期间表达ICP27时也有更高的磷酸化水平。此外，在野生型HSV-1感染期间，发现一种表观分子量为63 kDa的磷蛋白与抗Sm抗血清共免疫沉淀。ICP27的表观分子量为63 kDa，免疫印迹分析证实ICP27与snRNP共免疫沉淀。对整个ICP27蛋白的突变分析表明，这种相互作用所需的区域是蛋白的C末端，其中包括一个富含半胱氨酸-组氨酸的区域，类似于锌指样基序。这些数据表明，ICP27在感染期间与snRNP相互作用，并促进至少两种与snRNP免疫沉淀的蛋白的磷酸化状态发生变化，尽管这些研究没有证明它是直接还是间接这样做的。
