CHARACTERIZATION OF NOVIKOFF HEPATOMA MESSENGER-RNA METHYLATION AND HETEROGENEITY IN METHYLATED 5' TERMINUS
CHARACTERIZATION OF NOVIKOFF HEPATOMA MESSENGER-RNA METHYLATION AND HETEROGENEITY IN METHYLATED 5' TERMINUS
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DOI：
10.1021/bi00691a004
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发表时间：
1975-01-01
期刊：
影响因子：
2.9
通讯作者：
ROTTMAN, FM
中科院分区：
文献类型：
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作者：
DESROSIERS, RC;FRIDERICI, KH;ROTTMAN, FM
用KOH消化经（dT）-纤维素层析纯化的甲基标记的poly（A）+ mRNA，当用Pellionex-WAX高速液相层析在7 M尿素中基于电荷分离时，产生了monoclutide和大寡核苷酸的多个峰（-6至-8电荷）。在应用于（dT）-纤维素之前，需要RNA的热变性以释放污染物（主要是18 S rRNA），这些污染物即使在室温下与（dT）-纤维素重复结合后也持续存在。用酶消化、酸水解和各种层析技术对纯化的poly（A）+ mRNA进行分析，结果表明，单核苷酸肽（53%）完全是7 ′-6-甲基腺苷的产物。发现大的寡核苷酸（47%）含有7-甲基鸟苷和所有四个核苷的2，-O-甲基衍生物。未发现与poly（A）节段相关的放射性。mRNA的过碘酸盐氧化，随后的过碘酸盐消除仅释放标记的7-甲基鸟嘌呤，这与含有不寻常的5 '-5'键的封闭的5 '末端一致。阿尔-
KOH digestion of methyl-labeled poly (A)+ mRNA purified by (dT)-cellulose chromatography pro-duced mononucleotide and multiple peaks of a large oligonucleotide (—6 to—8 charge) when separated on the basis of charge by Pellionex-WAX high-speed liquid chromatography in 7 M urea. Heat denaturation of the RNA before application to (dT)-cellulose was required to release con-taminants (mostly 18S rRNA) that persisted even after re-peated binding to (dT)-cellulose at room temperature. Analysis of the purified poly (A)+ mRNA by enzyme diges-tion, acid hydrolysis, and a variety of chromatographic techniques has shown that the mononucleotide (53%) is due entirely to 7V6-methyIadenosine. The large oligonucleotides (47%) were found to contain 7-methylguanosine and the 2,-0-methyl derivatives of all four nucleosides. No radioac-tivity was found associated with the poly (A) segment. Per-iodate oxidation of the mRNA followed by ß elimination released only labeled 7-methylguanine consistent with a blocked 5'terminus containing an unusual 5'-5'bond. Al-