Feng Y X, Copeland T D, Henderson L E, Gorelick R J, Bosche W J, Levin J G, Rein A
Retroviral Genetics Section, National Cancer Institute-Frederick Cancer Research and Development Center, MD 21702-1201, USA.
Proc Natl Acad Sci U S A. 1996 Jul 23;93(15):7577-81. doi: 10.1073/pnas.93.15.7577.
After a retrovirus particle is released from the cell, the dimeric genomic RNA undergoes a change in conformation. We have previously proposed that this change, termed maturation of the dimer, is due to the action of nucleocapsid (NC) protein on the RNA within the virus particle. We now report that treatment of a 345-base synthetic fragment of Harvey sarcoma virus RNA with recombinant or synthetic HIV-1 NC protein converts a less stable form of dimeric RNA to a more stable form. This phenomenon thus appears to reproduce the maturation of dimeric retroviral RNA in a completely defined system in vitro. To our knowledge, maturation of dimeric RNA within a retrovirus particle is the first example of action of an "RNA chaperone" protein in vivo. Studies with mutant NC proteins suggest that the activity depends upon basic amino acid residues flanking the N-terminal zinc finger and upon residues within the N-terminal finger, including an aromatic amino acid, but do not require the zinc finger structures themselves.
逆转录病毒颗粒从细胞释放后，二聚体基因组RNA会发生构象变化。我们之前曾提出，这种被称为二聚体成熟的变化是由于核衣壳（NC）蛋白对病毒颗粒内RNA的作用。我们现在报告，用重组或合成的HIV-1 NC蛋白处理哈维肉瘤病毒RNA的一个345个碱基的合成片段，可将不太稳定的二聚体RNA形式转化为更稳定的形式。因此，这种现象似乎在一个完全明确的体外系统中重现了二聚体逆转录病毒RNA的成熟过程。据我们所知，逆转录病毒颗粒内二聚体RNA的成熟是“RNA伴侣”蛋白在体内作用的首个例子。对突变NC蛋白的研究表明，该活性取决于N端锌指两侧的碱性氨基酸残基以及N端指内的残基，包括一个芳香族氨基酸，但不需要锌指结构本身。
