Viral Mutation Section.
J Virol. 2013 Oct;87(20):11047-62. doi: 10.1128/JVI.02070-13. Epub 2013 Aug 7.
Mov10 and APOBEC3G (A3G) localize to cytoplasmic granules called processing bodies (P bodies), incorporate into human immunodeficiency virus type 1 (HIV-1) virions, and inhibit viral replication. The functional relevance of Mov10/A3G P-body localization to virion incorporation and antiviral activity has not been fully explored. We found that a helicase V mutant of Mov10 exhibits significantly reduced localization to P bodies but still efficiently inhibits viral infectivity via virion incorporation. Disruption of the P bodies by DDX6 knockdown also confirmed Mov10 antiviral activity without P-body localization. In addition, overexpression of SRP19, which binds to 7SL RNA, depleted A3G from P bodies but did not affect its virion incorporation. Sucrose gradient sedimentation assays revealed that the majority of Mov10, A3G, HIV-1 RNA, and Gag formed high-molecular-mass (HMM) complexes that are converted to low-molecular-mass (LMM) complexes after RNase A treatment. In contrast, the P-body markers DCP2, LSM1, eIF4e, DDX6, and AGO1 were in LMM complexes, whereas AGO2, an effector protein of the RNA-induced silencing complex that localizes to P bodies, was present in both LMM and HMM complexes. Depletion of AGO2 indicated that RNA-induced silencing function is required for Mov10's ability to reduce Gag expression upon overexpression, but not its virion incorporation or effect on virus infectivity. We conclude that the majority of Mov10 and A3G are in HMM complexes, whereas most of the P-body markers are in LMM complexes, and that virion incorporation and the antiviral activities of Mov10 and A3G do not require their localization to P bodies.
Mov10 和 APOBEC3G（A3G）定位于称为处理体（P 体）的细胞质颗粒中，整合到人类免疫缺陷病毒 1 型（HIV-1）病毒粒子中，并抑制病毒复制。Mov10/A3G P 体定位与病毒粒子整合和抗病毒活性的功能相关性尚未得到充分探索。我们发现 Mov10 的解旋酶 V 突变体显示出明显减少的 P 体定位，但仍通过病毒粒子整合有效地抑制病毒感染力。DDX6 敲低对 P 体的破坏也证实了 Mov10 的抗病毒活性而无需 P 体定位。此外，与 7SL RNA 结合的 SRP19 的过表达从 P 体中耗尽了 A3G，但不影响其病毒粒子整合。蔗糖梯度沉淀分析表明，大多数 Mov10、A3G、HIV-1 RNA 和 Gag 形成高分子质量（HMM）复合物，在用 RNase A 处理后转化为低分子质量（LMM）复合物。相比之下，P 体标记物 DCP2、LSM1、eIF4e、DDX6 和 AGO1 存在于 LMM 复合物中，而 AGO2，一种定位于 P 体的 RNA 诱导沉默复合物的效应蛋白，存在于 LMM 和 HMM 复合物中。AGO2 的耗尽表明 RNA 诱导的沉默功能是 Mov10 过表达时降低 Gag 表达的能力所必需的，但不是其病毒粒子整合或对病毒感染力的影响。我们得出结论，大多数 Mov10 和 A3G 位于 HMM 复合物中，而大多数 P 体标记物位于 LMM 复合物中，并且病毒粒子整合和 Mov10 和 A3G 的抗病毒活性不需要它们定位于 P 体。
