Martin K, Helenius A
Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06510.
J Virol. 1991 Jan;65(1):232-44. doi: 10.1128/JVI.65.1.232-244.1991.
Upon penetration of the influenza virus nucleocapsid into the host cell cytoplasm, the viral RNA and associated proteins are transported to the nucleus, where viral transcription and replication occur. By using quantitative confocal microscopy, we have found that over half of cell-associated nucleoprotein (NP) entered the nucleus with a half time of 10 min after penetration into CHO cells. Microinjection and immunoelectron microscopy experiments indicated that the NP entered the nucleus through the nuclear pore as part of an intact ribonucleoprotein (RNP) structure and that its transport was an active process. Transport of the incoming RNPs into the nucleus was not dependent on an intact microfilament, microtubule, or intermediate filament network. Subsequent to penetration, the matrix (M1) protein appeared to dissociate from the RNP structure and to enter the nucleus independently of the RNP. We found that 50% of penetrated M1 entered the nucleus with a half time of 25 min after penetration into CHO cells. Nuclear transport of M1 appeared to occur by passive diffusion. Entry of incoming M1 into the nucleus was not a prerequisite for infection.
流感病毒核衣壳进入宿主细胞质后，病毒RNA及相关蛋白被转运至细胞核，在细胞核内进行病毒转录和复制。通过定量共聚焦显微镜观察，我们发现超过半数与细胞结合的核蛋白（NP）在进入CHO细胞后10分钟内以半衰期进入细胞核。显微注射和免疫电子显微镜实验表明，NP作为完整核糖核蛋白（RNP）结构的一部分通过核孔进入细胞核，其转运是一个主动过程。进入的RNP向细胞核的转运不依赖于完整的微丝、微管或中间丝网络。穿透后，基质（M1）蛋白似乎与RNP结构解离，并独立于RNP进入细胞核。我们发现，50%的穿透性M1在进入CHO细胞后25分钟内以半衰期进入细胞核。M1的核转运似乎是通过被动扩散发生的。进入的M1进入细胞核不是感染的先决条件。
