Wallace J C, Wood W M, Edmonds M
Biochemistry. 1981 Sep 15;20(19):5364-8. doi: 10.1021/bi00522a002.
The 5'-terminal cap structures of 32P-labeled oligo(uridylic acid)-containing messenger ribonucleic acid [oligo(U+)mRNA] isolated from HeLa cell polyadenylated [poly(A+)] mRNA were analyzed and compared to those of the poly(A+) mRNA. A method employing P1 nuclease, alkaline phosphatase, and adsorption to activated charcoal showed that the types of cap core (m7 GpppXm) in oligo(U+) mRNA were essentially identical with those in poly(A+) mRNA. Analysis of RNase T2 digestion products of oligo(U+) mRNA demonstrated the presence of both cap 1 (m7GpppXmpYp) and cap 2 (m7GpppXmpYmpZp) in this subpopulation, confirming its cytoplasmic location. The base compositions of these two types of caps were different from each other and nonrandom but did not differ significantly between oligo(U+) and poly(A+) m RNA. The only observed difference between the mRNA populations was a higher ratio of cap 1 and cap 2 in the former. Possible implications of these findings for the relationship between oligo(U+) mRNA and poly(A+) mRNA are discussed.
对从HeLa细胞多聚腺苷酸化[poly(A+)] mRNA中分离出的含32P标记的寡聚（尿苷酸）信使核糖核酸[oligo(U+)mRNA]的5'-末端帽结构进行了分析，并与poly(A+) mRNA的帽结构进行了比较。一种采用P1核酸酶、碱性磷酸酶和吸附到活性炭上的方法表明，oligo(U+) mRNA中帽核心（m7GpppXm）的类型与poly(A+) mRNA中的基本相同。对oligo(U+) mRNA的RNase T2消化产物的分析表明，该亚群中同时存在帽1（m7GpppXmpYp）和帽2（m7GpppXmpYmpZp），证实了其在细胞质中的定位。这两种类型帽的碱基组成彼此不同且非随机，但oligo(U+)和poly(A+) mRNA之间没有显著差异。在mRNA群体之间唯一观察到的差异是前者中帽1和帽2的比例更高。讨论了这些发现对oligo(U+) mRNA和poly(A+) mRNA之间关系的可能影响。
