THE ROLE OF INTRACELLULAR TRAFFIC IN HIV INFECTION

细胞内运输在 HIV 感染中的作用

• 批准号: 3753979
• 负责人: J A HANOVER
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3753979
• 关键词: HIV infections; Xenopus oocyte; active transport; glycoproteins; guanosine triphosphate; human immunodeficiency virus; intracellular transport; nuclear membrane; nucleolus; virus RNA; virus protein; virus replication

Transport across the nuclear membrane is a necessary component of the life cycle of the human immunodeficiency virus (HIV). Once in the cytoplasm, HIV RNA is reverse-transcribed into double-stranded DNA which then must enter the nucleus. A growing amount of evidence points to the viral matrix protein of HIV as a mediator of this transport event. Efforts are underway to determine how the matrix protein may be involved in nuclear transport of the DNA-RNA-protein complex. In addition, other retroviral regulatory proteins also enter the nucleus, and viral transcripts are exported out to the cytoplasm. The viral proteins, rev and tat, have been identified as a key regulators of the transcription and transport of HIV envelope mRNA out of the nucleus. These proteins contain sequences that are necessary and sufficient for targeting to the nucleolus. An in Vitro system using permeabilized cells has been developed to look at the nucleolar targeting of proteins bearing such targeting signals. This nucleolar localization is blocked by reducing the temperature to 4 degrees C or by omitting ATP. This suggests that transport to the nucleolus is an active process. Recently, it has been demonstrated that a reduction in cellular GTP levels induced by inhibitors of IMP-dehydrogenase reduce the nucleolar accumulation of other nucleolar proteins. However, these inhibitors, which include ribavirin and mycophenolic acid, did not affect nucleolar accumulation of the model protein in permeabilized cells. Moreover, an 100-fold reduction of GTP levels in the in vitro assay did not affect nucleolar accumulation of the model protein. Our studies suggest that the loss of a protein with a rapid turnover rate may be responsible for the observed effect of IMP dehydrogenase inhibitors on nucleolar targeting. In other studies, the structure of the nuclear pore has been examined. Nuclei have been reconstituted from Xenopus laevis egg extracts with exogenous DNA. The reconstituted nuclei mimic interphase nuclei in many ways and carry out active nuclear transport, and also contain structures resembling nucleoli. The nuclear pore requires glycoprotein components for proper morphology and function.

核膜运输是核膜的必要组成部分。 人类免疫缺陷病毒(HIV)的生命周期。一次在 在细胞质中，HIV RNA被逆转录成双链DNA， 然后必须进入原子核。越来越多的证据表明 HIV的病毒基质蛋白作为这一运输事件的中介。 目前正在努力确定基质蛋白可能是如何参与的 在DNA-RNA-蛋白质复合体的核运输中。此外，其他 逆转录病毒调节蛋白也进入细胞核，病毒 转录产物被输出到细胞质中。病毒蛋白，REV 和Tat，已被确定为转录的关键调控因子 和HIV包膜mRNA的核外运输。这些蛋白质 包含的序列对于针对 核仁。一种使用渗透细胞的体外系统已经被 研究核仁靶向具有这样的蛋白质 瞄准信号。这种核仁的定位被阻止通过减少 将温度降至4摄氏度或省略三磷酸腺苷。这表明 向核仁的运输是一个活跃的过程。最近，它一直在 证明了细胞内GTP水平的降低是由 IMP-脱氢酶抑制剂减少核仁聚集 其他核仁蛋白。然而，这些抑制物包括 利巴韦林和霉酚酸不影响核仁聚集 模型蛋白在通透性细胞中的表达。此外，100倍的 体外实验中GTP水平的降低不影响核仁 模型蛋白的积累。我们的研究表明， 一种快速周转的蛋白质可能是造成观察到的 IMP脱氢酶抑制剂对核仁靶向的影响。在其他 研究表明，核孔的结构已被检查。原子核 是由非洲爪哇卵提取液与外源 DNA重组核在许多方面模仿相间核，并且 进行主动核运输，也包括构筑物 类似于核仁的。核孔需要糖蛋白成分 以获得适当的形态和功能。