Universität Würzburg, Institut für Virologie und Immunbiologie, Versbacher Str. 7, 97078 Würzburg, Germany.
Universität Würzburg, Institut für Virologie und Immunbiologie, Versbacher Str. 7, 97078 Würzburg, Germany.
Virology. 2014 Apr;454-455:145-56. doi: 10.1016/j.virol.2014.02.013. Epub 2014 Mar 4.
In contrast to orthoretroviruses, the foamy virus protease is only active as a protease-reverse transcriptase fusion protein and requires viral RNA for activation. Maturation of foamy viral proteins seems to be restricted to a single cleavage site in Gag and Pol. We provide evidence that unprocessed Gag is required for optimal infectivity, which is unique among retroviruses. Analyses of the cleavage site sequences of the Gag and Pol cleavage sites revealed a high similarity compared to those of Lentiviruses. We show that positions P2׳ and P2 are invariant and that Gag and Pol cleavage sites are processed with similar efficiencies. The RNase H domain is essential for protease activity, but can functionally be substituted by RNase H domains of other retroviruses. Thus, the RNase H domain might be involved in the stabilization of the protease dimer, while the RT domain is essential for RNA dependent protease activation.
与 orthoretroviruses 相反，泡沫病毒蛋白酶仅作为蛋白酶-逆转录酶融合蛋白发挥活性，并且需要病毒 RNA 来激活。泡沫病毒蛋白的成熟似乎仅限于 Gag 和 Pol 中的单个切割位点。我们提供的证据表明，未经处理的 Gag 是最佳感染性所必需的，这在逆转录病毒中是独特的。对 Gag 和 Pol 切割位点的切割位点序列的分析显示与 Lentiviruses 相比具有高度相似性。我们表明，位置 P2'和 P2 是不变的，并且 Gag 和 Pol 切割位点以相似的效率进行加工。RNase H 结构域对于蛋白酶活性是必需的，但可以通过其他逆转录病毒的 RNase H 结构域来替代。因此，RNase H 结构域可能参与蛋白酶二聚体的稳定，而 RT 结构域对于 RNA 依赖性蛋白酶激活是必需的。
