The HIV-1 Gag protein playing a key role in HIV-1 viral assembly has recently been shown to interact through its nucleocapsid domain with the ribosomal protein L7 (RPL7) that acts as a cellular co-factor promoting Gag's nucleic acid (NA) chaperone activity. To further understand how the two proteins act together, we examined their mechanism individually and in concert to promote the annealing between dTAR, the DNA version of the viral transactivation element and its complementary cTAR sequence, taken as model HIV-1 sequences. Gag alone or complexed with RPL7 was found to act as a NA chaperone that destabilizes cTAR stem-loop and promotes its annealing with dTAR through the stem ends via a two-step pathway. In contrast, RPL7 alone acts as a NA annealer that through its NA aggregating properties promotes cTAR/dTAR annealing via two parallel pathways. Remarkably, in contrast to the isolated proteins, their complex promoted efficiently the annealing of cTAR with highly stable dTAR mutants. This was confirmed by the RPL7-promoted boost of the physiologically relevant Gag-chaperoned annealing of (+)PBS RNA to the highly stable tRNA^Lys₃ primer, favoring the notion that Gag recruits RPL7 to overcome major roadblocks in viral assembly.

中文翻译：

---

HIV-1 Gag 多蛋白的核酸伴侣活性受到其细胞伙伴 RPL7 的增强：一项动力学研究。

HIV-1 Gag 蛋白在 HIV-1 病毒组装中发挥关键作用，最近已被证明通过其核衣壳结构域与核糖体蛋白 L7 (RPL7) 相互作用，核糖体蛋白 L7 充当促进 Gag 核酸 (NA) 伴侣的细胞辅助因子活动。为了进一步了解这两种蛋白质如何共同作用，我们分别检查了它们的机制，并共同检查了它们促进 dTAR（病毒反式激活元件的 DNA 版本）与其互补的 cTAR 序列（作为模型 HIV-1 序列）之间退火的机制。研究发现 Gag 单独或与 RPL7 复合可充当 NA 伴侣，使 cTAR 茎环不稳定，并通过两步途径促进其通过茎端与 dTAR 退火。相比之下，RPL7 单独充当 NA 退火剂，通过其 NA 聚集特性通过两条平行途径促进 cTAR/dTAR 退火。值得注意的是，与分离的蛋白质相比，它们的复合物有效地促进了 cTAR 与高度稳定的 dTAR 突变体的退火。RPL7 促进生理相关的 Gag 陪伴的 (+)PBS RNA 与高度稳定的 tRNA ^Lys ₃引物的退火增强证实了这一点，支持 Gag 招募 RPL7 来克服病毒组装中的主要障碍的观点。