Rein A, Harvin D P, Mirro J, Ernst S M, Gorelick R J
ABL-Basic Research Program, NCI-Frederick Cancer Research and Development Center, Maryland 21702.
J Virol. 1994 Sep;68(9):6124-9. doi: 10.1128/JVI.68.9.6124-6129.1994.
We have analyzed RNA packaging by a series of mutants altered in the nucleocapsid (NC) protein of Moloney murine leukemia virus (Mo-MuLV). We found that mutants lacking residues 8 through 11 or 44 through 60 of NC package Mo-MuLV RNA with virtually the same efficiency as wild-type Mo-MuLV. In contrast, point mutants altered at the conserved cysteines in the cysteine array (residues 26 and 29) and a mutant lacking residues 16 through 23 packaged Mo-MuLV RNA with approximately 1% of the efficiency of wild-type Mo-MuLV. The deficiency in packaged RNA was observed not only in Northern (RNA) analysis but also in an RNA-PCR assay, which would detect degraded as well as intact RNA. One of the cysteine array mutants was also shown to be defective with respect to encapsidation of hygromycin phosphotransferase mRNA containing a Mo-MuLV packaging signal. We suggest that a central region of NC, consisting of the cysteine array and flanking basic residues, is required for RNA packaging in Mo-MuLV.
我们通过一系列莫洛尼鼠白血病病毒（Mo-MuLV）核衣壳（NC）蛋白发生改变的突变体，对RNA包装进行了分析。我们发现，缺失NC蛋白第8至11位残基或第44至60位残基的突变体包装Mo-MuLV RNA的效率与野生型Mo-MuLV几乎相同。相比之下，在半胱氨酸阵列（第26和29位残基）中保守半胱氨酸处发生改变的点突变体以及缺失第16至23位残基的突变体包装Mo-MuLV RNA的效率约为野生型Mo-MuLV的1%。包装RNA的缺陷不仅在Northern（RNA）分析中观察到，在RNA-PCR检测中也观察到，RNA-PCR检测既能检测降解的RNA，也能检测完整的RNA。其中一个半胱氨酸阵列突变体在含有Mo-MuLV包装信号的潮霉素磷酸转移酶mRNA的衣壳化方面也表现出缺陷。我们认为，Mo-MuLV中RNA包装需要由半胱氨酸阵列和侧翼碱性残基组成的NC中央区域。
