Muthukrishnan S, Filipowicz W, Sierra J M, Both G W, Shatkin A J, Ochoa S
J Biol Chem. 1975 Dec 25;250(24):9336-41.
Cell-free protein-synthesizing extracts prepared from the brine shrimp, Artemia salina, translate methylated mRNAs. Reovirus unmethylated mRNA is inactive as a template when methylation is prevented by the inhibitor, S-adenosylhomocysteine. A salina mRNAs from both undeveloped and developed embryos contain 5'-terminal 7-methylguanosine in an inverted 5'-5' linkage through three phosphate groups to the rest of the polynucleotide chain. Removal of the 7-methylguanosine by beta elimination converts the mRNA from an active form to one inactive in protein synthesis in extracts of A. salina or wheat germ. Extracts of undeveloped and developed embryos methylate reovirus unmethylated mRNA at the 5' ends to form 5'-terminal structures of the type, m7G(5')ppp(5')G and m7G(5')ppp(5')Gm.
从卤虫（Artemia salina）制备的无细胞蛋白质合成提取物能够翻译甲基化的信使核糖核酸（mRNA）。当抑制剂S-腺苷高半胱氨酸阻止甲基化时，呼肠孤病毒未甲基化的mRNA作为模板是无活性的。来自未发育和发育胚胎的卤虫mRNA在5'端含有7-甲基鸟苷，通过三个磷酸基团以反向5'-5'连接与多核苷酸链的其余部分相连。通过β消除去除7-甲基鸟苷会将mRNA从活性形式转变为在卤虫或小麦胚芽提取物中蛋白质合成无活性的形式。未发育和发育胚胎的提取物在5'端将呼肠孤病毒未甲基化的mRNA甲基化，形成m7G(5')ppp(5')G和m7G(5')ppp(5')Gm类型的5'端结构。
