Fraenkel-Conrat H, Singer B
Proc Natl Acad Sci U S A. 1980 Apr;77(4):1983-5. doi: 10.1073/pnas.77.4.1983.
Treatment of RNA with dimethyl sulfate methylates only nitrogens, preferentially the 7 position of guanosine, whereas treatment with ethylnitrosourea ethylates mainly oxygens, preferentially the phosphodiester groups. Two plant viral mRNAs were modified with these two reagents at levels of 4-28 alkylations per molecule. The ability of alkylated RNAs to stimulate amino acid incorporation in the wheat germ system was somewhat diminished by both types of modification, but the predominant protein made, as ascertained by polyacrylamide gel electrophoresis, was the typical gene product of the respective mRNA. These data suggest that random alkylations, mostly of either the guanosine N-7s or the phosphates, do not interfere with peptide chain elongation, but that the ability to initiate translation properly is affected by these substitutions, presumably through their effect on the conformation of the RNAs.
用硫酸二甲酯处理RNA只会使氮甲基化，优先使鸟苷的7位氮甲基化，而用乙基亚硝基脲处理则主要使氧乙基化，优先使磷酸二酯基团乙基化。用这两种试剂对两种植物病毒mRNA进行修饰，修饰水平为每个分子4 - 28次烷基化。两种修饰都在一定程度上降低了烷基化RNA刺激小麦胚系统中氨基酸掺入的能力，但通过聚丙烯酰胺凝胶电泳确定，所产生的主要蛋白质是各自mRNA的典型基因产物。这些数据表明，随机烷基化，主要是鸟苷N - 7或磷酸基团的烷基化，不会干扰肽链延伸，但正确起始翻译的能力会受到这些取代的影响，推测是通过它们对RNA构象的影响。
