Méric C, Goff S P
Department of Biochemistry, College of Physicians and Surgeons, Columbia University, New York, New York 10032.
J Virol. 1989 Apr;63(4):1558-68. doi: 10.1128/JVI.63.4.1558-1568.1989.
To study the function of the retroviral nucleocapsid protein (NC), we have constructed point mutations in the gag gene of Moloney murine leukemia virus (MuLV) that affect a conserved cysteine-histidine motif of NC. The mutants were characterized biologically and biochemically. Cell lines producing the mutant virions were constructed in NIH 3T3 and rat2 cells, and the viral particles released by these cells were characterized for protein and RNA content. The results indicated that most mutations block replication and specifically inhibit the packaging of the MuLV genomic RNA. In some of the mutants, the packaging of the endogenous rat VL30 RNA was not affected as profoundly as was MuLV RNA. NC also seems to have another function distinct from dimer formation and packaging: one mutation reduced viral RNA packaging by only fivefold but completely abolished viral cDNA synthesis, suggesting a defect in reverse transcription.
为了研究逆转录病毒核衣壳蛋白（NC）的功能，我们在莫洛尼鼠白血病病毒（MuLV）的gag基因中构建了点突变，这些突变影响了NC中一个保守的半胱氨酸-组氨酸基序。对这些突变体进行了生物学和生物化学特性分析。在NIH 3T3和大鼠2细胞中构建了产生突变病毒粒子的细胞系，并对这些细胞释放的病毒颗粒的蛋白质和RNA含量进行了表征。结果表明，大多数突变会阻断复制，并特异性抑制MuLV基因组RNA的包装。在一些突变体中，内源性大鼠VL30 RNA的包装不像MuLV RNA那样受到严重影响。NC似乎还具有另一种不同于二聚体形成和包装的功能：一个突变仅使病毒RNA包装减少了五倍，但完全消除了病毒cDNA合成，这表明逆转录存在缺陷。
