Heinkelein M, Schmidt M, Fischer N, Moebes A, Lindemann D, Enssle J, Rethwilm A
Institut für Virologie und Immunbiologie, Universität Würzburg, Würzburg, Germany.
J Virol. 1998 Aug;72(8):6307-14. doi: 10.1128/JVI.72.8.6307-6314.1998.
To identify cis-acting elements in the foamy virus (FV) RNA pregenome, we developed a transient-vector-production system based on cotransfection of indicator gene-bearing vector and gag-pol and env expression plasmids. Two elements which were critical for vector transfer were found and mapped approximately. The first element was located in the RU5 leader and the 5' gag region (approximately up to position 650 of the viral RNA). The second element was located in an approximately 2-kb sequence in the 3' pol region. Although small 5' and 3' deletions, as well as internal deletions of the latter element, were tolerated, both elements were found to be absolutely required for vector transfer. The functional characterization of the pol region-located cis-acting element revealed that it is essential for efficient incorporation or the stability of particle-associated virion RNA. Furthermore, virions derived from a vector lacking this sequence were found to be deficient in the cleavage of the Gag protein by the Pol precursor protease. Our results suggest that during the formation of infectious virions, complex interactions between FV Gag and Pol and the viral RNA take place.
为了鉴定泡沫病毒（FV）RNA前基因组中的顺式作用元件，我们基于共转染携带指示基因的载体以及gag-pol和env表达质粒，开发了一种瞬时载体生产系统。发现了两个对载体转移至关重要的元件并大致进行了定位。第一个元件位于RU5前导序列和5' gag区域（大约到病毒RNA的第650位）。第二个元件位于3' pol区域中一个约2 kb的序列中。尽管较小的5'和3'缺失以及后一个元件的内部缺失是可耐受的，但发现这两个元件对于载体转移都是绝对必需的。对位于pol区域的顺式作用元件的功能表征表明，它对于有效包装或颗粒相关病毒体RNA的稳定性至关重要。此外，发现源自缺乏该序列的载体的病毒体在Pol前体蛋白酶切割Gag蛋白方面存在缺陷。我们的结果表明，在感染性病毒体形成过程中，FV Gag和Pol与病毒RNA之间发生了复杂的相互作用。
