Turner Peter C, Dilling Bradley P, Prins Cindy, Cresawn Steven G, Moyer Richard W, Condit Richard C
Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610-0266, USA.
Virology. 2007 Sep 15;366(1):62-72. doi: 10.1016/j.virol.2007.03.060. Epub 2007 May 17.
The vaccinia virus temperature-sensitive mutations Cts6 and Cts9 were mapped by marker rescue and DNA sequencing to the A28 gene. Cts6 and Cts9 contain an identical 2-bp deletion truncating the A28 protein and removing the fourth conserved cysteine near the C-terminus. Cts9 mutant virions produced at 40 degrees C were non-infectious and unable to cause cytopathic effect. However, the mutant A28 protein localized to purified mature virions (MV) at 31 degrees C and 40 degrees C. MV of Cts9 produced at 40 degrees C bound to cells but did not enter cells. Low pH treatment of Cts9-infected cells at 18 h p.i. failed to produce fusion from within at 40 degrees C, but gave fusion at 31 degrees C. Adsorption of Cts9 mutant virions to cells followed by low pH treatment showed a defect in fusion from without. The Cts9 phenotype suggests that the A28 protein is involved in both virus entry and cell-cell fusion, and supports the linkage between the two processes.
通过标记拯救和DNA测序，将痘苗病毒温度敏感突变Cts6和Cts9定位到A28基因。Cts6和Cts9包含一个相同的2碱基缺失，该缺失截断了A28蛋白并去除了C末端附近的第四个保守半胱氨酸。在40℃产生的Cts9突变体病毒粒子无感染性，且无法引起细胞病变效应。然而，突变的A28蛋白在31℃和40℃时定位于纯化的成熟病毒粒子（MV）。在40℃产生的Cts9的MV与细胞结合但未进入细胞。在感染后18小时对感染Cts9的细胞进行低pH处理，在40℃时未能产生胞内融合，但在31℃时产生了融合。Cts9突变体病毒粒子吸附到细胞上后进行低pH处理，显示出胞外融合缺陷。Cts9的表型表明A28蛋白参与病毒进入和细胞-细胞融合，并支持这两个过程之间的联系。
