Cartellieri Marc, Herchenröder Ottmar, Rudolph Wolfram, Heinkelein Martin, Lindemann Dirk, Zentgraf Hanswalter, Rethwilm Axel
Institut für Virologie, Medizinische Fakultät, Technische Universität Dresden, Germany.
J Virol. 2005 Oct;79(19):12464-76. doi: 10.1128/JVI.79.19.12464-12476.2005.
Among the Retroviridae, foamy viruses (FVs) exhibit an unusual way of particle assembly and a highly specific incorporation of envelope protein into progeny virions. We have analyzed deletions and point mutants of the prototypic FV gag gene for capsid assembly and egress, envelope protein incorporation, infectivity, and ultrastructure. Deletions introduced at the 3' end of gag revealed the first 297 amino acids (aa) to be sufficient for specific Env incorporation and export of particulate material. Deletions introduced at the 5' end showed the region between aa 6 and 200 to be dispensable for virus capsid assembly but required for the incorporation of Env and particle egress. Point mutations were introduced in the 5' region of gag to target residues conserved among FVs from different species. Alanine substitutions of residues in a region between aa 40 and 60 resulted in severe alterations in particle morphology. Furthermore, at position 50, this region harbors the conserved arginine that is presumably at the center of a signal sequence directing FV Gag proteins to a cytoplasmic assembly site.
在逆转录病毒科中，泡沫病毒（FV）呈现出一种不同寻常的病毒粒子组装方式，并且包膜蛋白以高度特异性的方式掺入子代病毒粒子中。我们分析了原型FV gag基因的缺失突变体和点突变体在衣壳组装与释放、包膜蛋白掺入、感染性及超微结构方面的情况。在gag基因3'端引入的缺失突变表明，最初的297个氨基酸（aa）足以实现包膜蛋白的特异性掺入以及颗粒物质的输出。在5'端引入的缺失突变显示，第6至200个氨基酸之间的区域对于病毒衣壳组装并非必需，但对于包膜蛋白的掺入和病毒粒子释放却是必需的。在gag基因的5'区域引入点突变，以靶向不同物种FV中保守的残基。第40至60个氨基酸之间区域内残基的丙氨酸替代导致病毒粒子形态发生严重改变。此外，在第50位，该区域含有保守的精氨酸，推测其位于将FV Gag蛋白导向细胞质组装位点的信号序列中心。
