Paik S Y, Banerjea A C, Harmison G G, Chen C J, Schubert M
Laboratory of Molecular Medicine and Neuroscience, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland 20892, USA.
J Virol. 1995 Jun;69(6):3529-37. doi: 10.1128/JVI.69.6.3529-3537.1995.
Besides its role in viral assembly, the vesicular stomatitis virus (VSV) matrix (M) protein causes cytopathic effects such as cell rounding (D. Blondel, G. G. Harmison, and M. Schubert, J. Virol. 64:1716-1725, 1990). DNA cotransfection assays demonstrated that VSV M protein was able to inhibit the transcription of a reporter gene (B. L. Black and D. S. Lyles, J. Virol. 66:4058-4064, 1992). We have confirmed these observations by using cotransfections with an infectious clone of human immunodeficiency virus type 1 (HIV-1) and found that the amino-terminal 32 amino acids of M protein which are essential for viral assembly were not required for this inhibition. For the study of the potential role of M protein in the shutoff of transcription from chromosomal DNA, we have isolated stable HeLa T4 cell lines which encode either a wild-type or a temperature-sensitive (ts) VSV M gene under control of the HIV-1 long terminal repeat promoter. Transcription of the M mRNA was transactivated after HIV-1 infections. A cell line which encodes the wild-type M protein was nonpermissive for either HIV-1 or HIV-2. A cell line that encodes the ts M gene was transfected with the infectious HIV-1 DNA or was infected with HIV-1 or HIV-2. In all cases, at 32 degrees C, the permissive temperature for M protein, the cells were nonpermissive for HIV replication. At 40 degrees C, the ts M protein was nonfunctional and both HIV-1 and HIV-2 were able to replicate at high levels. A comparison of the amounts of proviral HIV-1 DNAs and HIV-1 mRNAs at 10 and 36 h after HIV-1 infection demonstrated that proviral insertion had not been prevented by M protein and that the block in HIV-1 replication was at the level of proviral expression. The severe reduction of HIV-1 proviral transcripts demonstrates that the VSV M protein alone can inhibit expression from chromosomal DNA. These results strongly support the hypothesis that the VSV M protein is involved in the shutoff of host cell transcription. M protein was able to attenuate HIV-1 infections and protect the cell population from HIV-1 pathogenesis. The temperature-dependent switch from a persistent to a lytic HIV-1 infection in the presence of ts M protein could be useful for studies of HIV-1 replication and pathogenesis.
除了在病毒组装中的作用外，水泡性口炎病毒（VSV）基质（M）蛋白还会引起细胞病变效应，如细胞变圆（D. 布隆德尔、G.G. 哈米森和M. 舒伯特，《病毒学杂志》64:1716 - 1725，1990）。DNA共转染试验表明，VSV M蛋白能够抑制报告基因的转录（B.L. 布莱克和D.S. 莱尔斯，《病毒学杂志》66:4058 - 4064，1992）。我们通过用人免疫缺陷病毒1型（HIV - 1）的感染性克隆进行共转染证实了这些观察结果，并发现病毒组装所必需的M蛋白氨基末端32个氨基酸对于这种抑制作用并非必需。为了研究M蛋白在阻断染色体DNA转录中的潜在作用，我们分离了稳定的HeLa T4细胞系，这些细胞系在HIV - 1长末端重复启动子的控制下编码野生型或温度敏感型（ts）VSV M基因。HIV - 1感染后，M mRNA的转录被激活。编码野生型M蛋白的细胞系对HIV - 1或HIV - 2均无感染性。编码ts M基因的细胞系用感染性HIV - 1 DNA转染或感染HIV - 1或HIV - 2。在所有情况下，在32℃（M蛋白的允许温度）时，细胞对HIV复制无感染性。在40℃时，ts M蛋白无功能，HIV - 1和HIV - 2均能高水平复制。比较HIV - 1感染后10小时和36小时原病毒HIV - 1 DNA和HIV - 1 mRNA的量表明，M蛋白并未阻止原病毒的插入，并且HIV - 1复制的阻断发生在原病毒表达水平。HIV - 1原病毒转录本的严重减少表明，单独的VSV M蛋白就能抑制染色体DNA的表达。这些结果有力地支持了VSV M蛋白参与宿主细胞转录阻断的假说。M蛋白能够减弱HIV - 1感染并保护细胞群体免受HIV - 1致病作用。在存在ts M蛋白的情况下，从持续性HIV - 1感染到溶解性HIV - 1感染的温度依赖性转变可能有助于HIV - 1复制和致病机制的研究。
