Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112, USA.
Viruses. 2021 Sep 28;13(10):1946. doi: 10.3390/v13101946.
Immature HIV virions harbor a lattice of Gag molecules with significant ordering in CA-NTD, CA-CTD and SP1 regions. This ordering plays a major role during HIV maturation. To test the condition in which the Gag lattice forms in vivo, we assembled virus like particles (VLPs) by expressing only HIV Gag in mammalian cells. Here we show that these VLPs incorporate a similar number of Gag molecules compared to immature HIV virions. However, within these VLPs, Gag molecules diffuse with a pseudo-diffusion rate of 10 nm/s, this pseudo-diffusion is abrogated in the presence of melittin and is sensitive to mutations within the SP1 region. Using cryotomography, we show that unlike immature HIV virions, in the Gag lattice of VLPs the CA-CTD and SP1 regions are significantly less ordered. Our observations suggest that within immature HIV virions, other viral factors in addition to Gag, contribute to ordering in the CA-CTD and SP1 regions.
不成熟的 HIV 病毒体携带有大量 Gag 分子的晶格，在 CA-NTD、CA-CTD 和 SP1 区域具有显著的有序性。这种有序性在 HIV 成熟过程中起着重要作用。为了测试 Gag 晶格在体内形成的条件，我们仅在哺乳动物细胞中表达 HIV Gag 来组装病毒样颗粒 (VLPs)。在这里，我们表明这些 VLPs 与不成熟的 HIV 病毒体相比，掺入了相似数量的 Gag 分子。然而，在这些 VLPs 中，Gag 分子以 10nm/s 的拟扩散速率扩散，这种拟扩散在蜂毒素存在下被消除，并且对 SP1 区域内的突变敏感。使用冷冻断层成像技术，我们表明与不成熟的 HIV 病毒体不同，在 VLPs 的 Gag 晶格中，CA-CTD 和 SP1 区域的有序性显著降低。我们的观察结果表明，在不成熟的 HIV 病毒体中，除了 Gag 之外，其他病毒因子也有助于 CA-CTD 和 SP1 区域的有序性。
