Inhibition of RNA synthesis in mouse myeloma cells infected with vesicular stomatitis virus
Inhibition of RNA synthesis in mouse myeloma cells infected with vesicular stomatitis virus
复制标题
水泡性口炎病毒感染小鼠骨髓瘤细胞RNA合成的抑制
作者：
P. Weck;R. Wagner
水疱性口炎（VS）病毒感染小鼠骨髓瘤细胞（MPC-11）导致细胞RNA合成迅速显著减少，细胞活力受到损害。小鼠骨髓瘤细胞对病毒感染的应答倍数为1，且明显高于小鼠；比小鼠L细胞和BHK-21细胞对RNA合成的关闭更敏感。这种细胞RNA合成的抑制被证明不是由感染和未感染的MPC-11细胞对[3H]尿苷的不同膜透性引起的，也不是由于先前合成的RNA的更大降解。VS病毒感染似乎不妨碍新合成的核RNA向细胞质的转运；此外，感染细胞积累聚腺苷化mRNA的速度与未感染细胞相同。新合成的核RNA的聚丙烯酰胺凝胶电泳结果表明，其多分散性和大小分布不受VS病毒感染的影响。受感染的MPC-11细胞的分离细胞核也抑制了严重受损的合成RNA的能力，尽管缺乏细胞质因子。感染细胞的细胞质不会抑制未感染细胞核的转录，也不会逆转病毒对细胞核转录的抑制。α -amanitin的研究表明，VS病毒感染抑制了聚合酶I、II和III的活性，但只有聚合酶II在感染过程中逐渐受到影响，且影响程度更大。这些数据表明，即使在感染的低多重度下，VS病毒也能在核转录水平上迅速关闭细胞RNA合成。
Infection of mouse myeloma cells (MPC-11) with vesicular stomatitis (VS) virus resulted in rapid and marked reduction in cellular RNA synthesis considerably before cell viability was compromised. Mouse myeloma cells responded maximally to viral infection at a multiplicity of 1 and were considerably more se;sitive to shut-off of RNA synthesis than were mouse L cells or BHK-21 cells. This inhibition of cellular RNA synthesis was shown not to be caused by differential membrane permeability of infected and uninfected MPC-11 cells to [3H]uridine, nor was it due to greater degradation of previously synthesized RNA. VS viral infection appeared not to impede transport of newly synthesized nuclear RNA to the cytoplasm; moreover, infected cells accumulated polyadenylated mRNA at the same rate as did uninfected cells. Polyacrylamide gel electrophoresis of newly synthesized nuclear RNA demonstrated that the polydisperse nature and size distribution were not affected by VS viral infection. Isolated nuclei of infected MPC-11 cells also inhibited greatly impaired capacity to synthesize RNA despite the absence of cytoplasmic factors. Infected-cell cytosol did not inhibit transcription by uninfected-cell nuclei, nor did uninfected-cell cytosol reverse viral inhibition of nuclear transcription. Studies with alpha-amanitin revealed that VS viral infection inhibited the activity of polymerases I, II, and III, but only polymerase II was affected progressively throughout infection and to a much greater extent. These data suggest that, even at low multiplicities of infection, VS virus rapidly shuts off cellular RNA synthesis at the level of nuclear transcription.