Wiegand Marian A, Bossow Sascha, Schlecht Sabine, Neubert Wolfgang J
Department of Molecular Virology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
J Virol. 2007 Dec;81(24):13835-44. doi: 10.1128/JVI.00914-07. Epub 2007 Sep 12.
Among the members of the paramyxovirus family, the transcription process and the components involved have been studied under in vitro conditions thus far. Here, we reexamined the function of the viral RNA-dependent RNA polymerase through infection studies with Sendai virus (SeV) N and P deletion (Delta) mutants. To elucidate solely transcription-specific processes, all virus mutants also were rendered deficient in genome replication. Using mutant SeV DeltaP, the earlier suspected supplemental role of P protein was clearly demonstrated to be essential during viral gene expression. Moreover, when SeV DeltaN or DeltaN PDelta2-77 (with the 5' end of the P gene deleted) mutant was used for infections, a completely unexpected new and essential role for N protein was discovered for viral gene expression. In the early phases of an infection and in the absence of de novo viral protein synthesis, primary transcription occurs at hardly detectable levels. In contrast, if newly synthesized N protein is present, primary viral transcription reaches normal levels. From our data, we conclude that de novo synthesis of SeV N and P proteins is a key step for viral gene expression that facilitates the transition from preliminary to normal primary transcriptional activity.
在副粘病毒家族成员中，迄今为止，转录过程及其相关成分已在体外条件下进行了研究。在此，我们通过对仙台病毒（SeV）N和P缺失（Δ）突变体的感染研究，重新审视了病毒RNA依赖性RNA聚合酶的功能。为了单独阐明转录特异性过程，所有病毒突变体在基因组复制方面也存在缺陷。使用突变体SeV ΔP，早期怀疑的P蛋白的补充作用在病毒基因表达过程中被明确证明是必不可少的。此外，当使用SeV ΔN或ΔN PΔ2 - 77（P基因5'端缺失）突变体进行感染时，发现N蛋白在病毒基因表达中具有全新且意想不到的重要作用。在感染的早期阶段且不存在从头合成的病毒蛋白时，初级转录几乎以难以检测到的水平发生。相比之下，如果存在新合成的N蛋白，初级病毒转录可达到正常水平。根据我们的数据，我们得出结论，SeV N和P蛋白的从头合成是病毒基因表达的关键步骤，它促进了从初步到正常初级转录活性的转变。
