Mutations in the activation region of herpes simplex virus regulatory protein ICP27 can be trans dominant.
Mutations in the activation region of herpes simplex virus regulatory protein ICP27 can be trans dominant.
复制标题
单纯疱疹病毒调节蛋白ICP27激活区的突变可以是反式显性的。
DOI：
10.1128/jvi.65.7.3656-3666.1991
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发表时间：
1991
影响因子：
5.4
通讯作者：
Sandri-Goldin,RM
中科院分区：
文献类型：
--
作者：
Smith,IL;Sekulovich,RE;Hardwicke,MA;Sandri-Goldin,RM
单纯疱疹病毒1型(HSV-1)即刻早期蛋白ICP27是病毒复制所必需的调节蛋白。转染实验表明，ICP27与HSV-1反式激活剂ICP4和ICP0一起，可以正向调节某些晚期HSV-1靶质粒的表达，而负性调节某些即刻-早期和早期靶质粒的表达。我们先前发现，在激活晚期靶质粒方面有缺陷的突变体映射到蛋白质的羧基末端一半，而在ICP27的C端78个氨基酸中映射到ICP27的C端78个氨基酸内的突变体(M.A.Hardwicke，P.J.Vaughan，R.E.Sekulovich，R.O‘Conner和R.M.Sandri-Goldin，J.Virol)。63：4590-4602,1989)。在本研究中，我们将ICP27激活子和抑制子突变体与野生型ICP27共转染，以确定这些突变体是否会干扰野生型ICP27的活性。只有激活功能缺陷的突变体对野生型蛋白具有显性作用，并抑制晚期靶质粒pVP5-CAT的激活，而抑制功能缺陷的突变体既不抑制pVP5-CAT的激活，也不抑制早期靶质粒pTK-CAT的抑制。此外，稳定携带三种不同激活剂突变体的细胞系支持野生型HSV-1株Kos的能力受到损害，导致病毒产量比对照细胞低5-40倍。病毒复制的缺陷似乎源于HSV-1晚期基因产物在感染期间表达的减少，这是通过稳态mRNA水平和特定多肽的免疫沉淀分析来衡量的。这些结果表明，ICP27激活子突变在转染和感染过程中都特异性地干扰了蛋白质的激活功能。此外，这些结果表明，抑制区可能对多肽的结合很重要，因为该区域的突变不会干扰野生型ICP27的活性，因此可能不会竞争结合。
The herpes simplex virus type 1 (HSV-1) immediate-early protein ICP27 is an essential regulatory protein which is required for virus replication. Transfection experiments have demonstrated that ICP27 along with the HSV-1 transactivators ICP4 and ICP0 can positively regulate the expression of some late HSV-1 target plasmids and can negatively regulate the expression of some immediate-early and early target plasmids. We previously showed that mutants defective in the activation of a late target plasmid mapped to the carboxy-terminal half of the protein, whereas mutants defective in the repression of an early target plasmid mapped within the C-terminal 78 amino acids of ICP27 (M. A. Hardwicke, P. J. Vaughan, R. E. Sekulovich, R. O'Conner, and R. M. Sandri-Goldin, J. Virol. 63:4590-4602, 1989). In this study, we cotransfected ICP27 activator and repressor mutants along with wild-type ICP27 plasmid to determine whether these mutants could interfere with the wild-type activities. Mutants which were defective only in the activation function were dominant to the wild-type protein and inhibited the activation of the late target plasmid pVP5-CAT, whereas mutants defective in the repressor function did not inhibit either the activation of pVP5-CAT or the repression of the early target plasmid pTK-CAT. Furthermore, cell lines which stably carried three different activator mutants were impaired in their ability to support the growth of wild-type HSV-1 strain KOS, resulting in virus yields 5- to 40-fold lower than in control cells. The defect in virus replication appeared to stem from a decrease in the expression of HSV-1 late gene products during infection as measured by steady-state mRNA levels and by immunoprecipitation analysis of specific polypeptides. These results indicate that ICP27 activator mutations specifically interfere with the activation function of the protein both in transfection and during infection. Moreover, these results suggest that the repressor region may be important for binding of the polypeptide, since mutations in this region did not interfere with the activities of wild-type ICP27 and therefore presumably could not compete for binding.