Prats A C, Housset V, de Billy G, Cornille F, Prats H, Roques B, Darlix J L
Centre de Recherche de Biochimie et Génétique Cellulaires du CNRS, Toulouse, France.
Nucleic Acids Res. 1991 Jul 11;19(13):3533-41. doi: 10.1093/nar/19.13.3533.
The zinc fingers of retroviral gag nucleocapsid proteins (NC) are required for the specific packaging of the dimeric RNA genome into virions. In vitro, NC proteins activate both dimerization of viral RNA and annealing of the replication primer tRNA onto viral RNA, two reactions necessary for the production of infectious virions. In this study the role of the zinc finger of Moloney murine leukemia virus (MoMuLV) NCp10 in RNA binding and annealing activities was investigated through modification or replacement of residues involved in zinc coordination. These alterations did not affect the ability of NCp10 to bind RNA and promote RNA annealing in vitro, despite a complete loss of zinc affinity. However mutation of two conserved lysine residues adjacent to the finger motif reduced both RNA binding and annealing activities of NCp10. These findings suggest that the complexed NC zinc finger is not directly involved in RNA-protein interactions but more probably in a zinc dependent conformation of NC protein modulating viral protein-protein interactions, essential to the process of viral RNA selection and virion assembly. Then the NC zinc finger may cooperate to select the viral RNA genome to be packaged into virions.
逆转录病毒gag核衣壳蛋白（NC）的锌指对于将二聚体RNA基因组特异性包装到病毒粒子中是必需的。在体外，NC蛋白可激活病毒RNA的二聚化以及复制引物tRNA与病毒RNA的退火，这是产生感染性病毒粒子所必需的两个反应。在本研究中，通过修饰或替换参与锌配位的残基，研究了莫洛尼鼠白血病病毒（MoMuLV）NCp10的锌指在RNA结合和退火活性中的作用。尽管锌亲和力完全丧失，但这些改变并未影响NCp10在体外结合RNA和促进RNA退火的能力。然而，与指基序相邻的两个保守赖氨酸残基的突变降低了NCp10的RNA结合和退火活性。这些发现表明，复合的NC锌指并不直接参与RNA-蛋白质相互作用，而更可能参与NC蛋白的锌依赖性构象，调节病毒蛋白-蛋白质相互作用，这对于病毒RNA选择和病毒粒子组装过程至关重要。然后，NC锌指可能协同作用以选择要包装到病毒粒子中的病毒RNA基因组。
