The role of L* protein of Theiler's murine encephalomyelitis virus (TMEV)

我们报道了Theiler小鼠脑脊髓炎病毒（TMEV）的DA株在巨噬细胞中生长，TMEV在慢性感染阶段持续存在，从而维持基因组。另一方面，TMEV的GDVII株不能在那里生长，不能维持基因组。这种毒株特异性病毒生长仅在巨噬细胞中观察到，而在其他类型的细胞（宿主细胞依赖性病毒生长）中没有观察到。不产生L*-的DA病毒表明，L*蛋白与多蛋白相框外，从L编码区替代AUG翻译而来，在这一现象中起重要作用（J Virol 71: 729-733, 1997; J Virol 72: 4950-4955, 1998；微生物免疫学报，43:885-892,1999）。在以上数据的基础上，我们利用产生L*的GDVII病毒证实了L*蛋白的重要性。此外，RNase保护实验表明，宿主细胞依赖性株特异性病毒的生长在RNA复制的步骤中受到调节[J] .中国生物医学工程学报，24(4):998 - 901,2000)。为了表征L*蛋白，我们使用了一种针对合成肽的抗体。它的合成动力学与其他病毒蛋白相似，但数量较少。它在细胞质中保持稳定，不并入病毒粒子。免疫染色显示其与微管有关（病毒学289:95-102,2001）。

We have reported that DA strain of Theiler' s murine encephalomyelitis virus (TMEV) grows in macrophages where TMEV persists in the chronic stage of infection, therefore maintaining the genome. On the other hand, GDVII strain of TMEV does not grow there, and cannot maintain the genome. Such strain-specific virus growth was observed only in macrophages, but not in other types of cells (host cell-dependent virus growth). L*-nonproducing DA virus demonstrated that L* protein, which is out-of-frame with the polyprotein and translated from the alternative AUG within the L coding region, plays an important role for this phenomenon (J Virol 71: 729-733, 1997; J Virol 72: 4950-4955, 1998; Microbiol Immunol, 43: 885-892, 1999).On the basis of the above data, we confirmed the importance of L* protein by using L*-producing GDVII viurs. In addition, RNase proteiction assay deomstrated that host-cell dependant strainspecific virus growth is regulated at the step of RNA replication J Virol 74: 4898-4901, 2000). In order to characterize L* protein, we used an antibody raised against a synthetic peptide. It was synthesized with kinetics similar to that of other viral proteins although less in amount. It remained stable in the cytoplasm and was not incorporated into virions. Immunostaining demonstrated that it was associated witn microtubules (Virology 289: 95-102, 2001).