Morrison T G, Lodish H F
Proc Natl Acad Sci U S A. 1973 Feb;70(2):315-9. doi: 10.1073/pnas.70.2.315.
Cytoplasmic extracts from Krebs II mouse ascites cells and from L cells translate messenger RNA from coliphage Qbeta with fidelity to produce products that migrate on polyacrylamide gels with those products directed by Qbeta RNA in an Escherichia coli cell-free system. The mammalian cell extracts correctly initiate and terminate Qbeta coat protein synthesis, as shown by: (i) [(3)H]lysine-and [(3)H]arginine-labeled tryptic peptides derived from the coat-sized product resemble these from authentic Qbeta coat protein, (ii) Qbeta coat (which contains methionine only at the N-terminal end) can be radioactively labeled with methionine only if the methionine is formylated, and (iii) L cell extracts directed by Qbeta am(-)11 (an amber mutant in the coat protein) RNA make no completed coat-sized material, but do make a peptide the size of the authentic amber coat fragment.
来自克雷布斯II型小鼠腹水细胞和L细胞的细胞质提取物能够忠实地翻译噬菌体Qβ的信使RNA,从而产生在聚丙烯酰胺凝胶上迁移的产物,这些产物与在大肠杆菌无细胞系统中由Qβ RNA指导产生的产物相同。哺乳动物细胞提取物能够正确地起始和终止Qβ外壳蛋白的合成,这表现为:(i) 从外壳大小的产物衍生而来的经[³H]赖氨酸和[³H]精氨酸标记的胰蛋白酶肽与来自天然Qβ外壳蛋白的肽相似;(ii) Qβ外壳蛋白(仅在N端含有甲硫氨酸)只有在甲硫氨酸被甲酰化时才能被放射性标记;(iii) 由Qβ am(-)11(外壳蛋白中的一个琥珀突变体)RNA指导的L细胞提取物不会产生完整的外壳大小的物质,但会产生与天然琥珀外壳片段大小相同的肽。