Wallace J C, Edmonds M
Proc Natl Acad Sci U S A. 1983 Feb;80(4):950-4. doi: 10.1073/pnas.80.4.950.
A highly charged component can be isolated from a total RNase T2 digest of nuclear polyadenylylated RNA from HeLa cells that is separable from caps by (dihydroxyboryl)aminoethyl-cellulose chromatography. Chemical and enzymatic analyses show that the component contains a 2'-5' phosphodiester bond that creates a branch at the 2'-hydroxyl group of one nucleotide already linked to an adjoining nucleotide through the usual 3'-5' phosphodiester bond. [Formula: see text] This structure was confirmed by analysis of a similar component isolated from nuclease P1 digests of the same nuclear polyadenylylated RNA. Branches occur in roughly 10% of nuclear polyadenylylated RNAs, including those >10S in size, but are absent from cytoplasmic polyadenylylated RNA. Possible implications for branches as intermediates in mRNA processing are discussed.
一种高电荷成分可从HeLa细胞核多聚腺苷酸化RNA的总核糖核酸酶T2消化产物中分离出来，通过（二羟基硼基）氨基乙基纤维素色谱法可将其与帽结构分离。化学和酶学分析表明，该成分含有一个2'-5'磷酸二酯键，该键在一个已通过通常的3'-5'磷酸二酯键与相邻核苷酸相连的核苷酸的2'-羟基处形成一个分支。[化学式：见正文]通过对从相同核多聚腺苷酸化RNA的核酸酶P1消化产物中分离出的类似成分的分析，证实了这种结构。分支大约出现在10%的核多聚腺苷酸化RNA中，包括那些大小大于10S的RNA，但在细胞质多聚腺苷酸化RNA中不存在。讨论了分支作为mRNA加工中间体的可能影响。
