假定的珠蛋白信使核糖核酸15S前体含有一个多聚腺苷酸序列。

The putative 15 S precursor of globin mRNA contains a poly (A) sequence.

作者信息

Knöchel W, Grundmann U

出版信息

Biochim Biophys Acta. 1978 Jan 26;517(1):99-108. doi: 10.1016/0005-2787(78)90037-0.

Abstract

[3H] Uridine or [3H] adenosine pulse-labelled nuclear RNA was isolated from chicken immature red blood cells and separated on denaturing formamide sucrose gradients. RNA of each gradient fraction was hybridized with unlabelled globin DNA complementary to mRNA (cDNA) and subsequently digested by RNAase A and RNAase T1. The experiments revealed two RNA species with globin coding sequences sedimenting 9 S and approx. 15 S, the latter probably representing a precursor of 9 S globin mRNA. A poly (A) sequence was demonstrated in this RNA by two different approaches. Nuclear RNA pulse-labelled with [3H] uridine was fractionated by chromatography on poly (U)-Sepharose. Part of the 15 S precursor was found in the poly(A)-containing RNA. In the second approach 15 S RNA pulse-labelled with [3H]adenosine was hybridized with globin cDNA, incubated with RNAase A and RNAase T1 and subjected to chromatography on hydroxyapatite. The hybrids were isolated and after separation of the strands degraded with DNAase I, RNAase A and RNAase T1. By this procedure poly(A) sequences of approximately 100 nucleotides could be isolated from the 15 S RNA with globin coding sequences. The poly(A) sequence was completely degraded by RNAase T2.

摘要

从鸡未成熟红细胞中分离出用[³H]尿苷或[³H]腺苷脉冲标记的核RNA，并在变性甲酰胺蔗糖梯度上进行分离。每个梯度级分的RNA与与mRNA互补的未标记珠蛋白DNA（cDNA）杂交，随后用核糖核酸酶A和核糖核酸酶T1消化。实验揭示了两种具有珠蛋白编码序列的RNA种类，沉降系数分别为9S和约15S，后者可能代表9S珠蛋白mRNA的前体。通过两种不同方法在这种RNA中证实了多聚（A）序列。用[³H]尿苷脉冲标记的核RNA通过在聚（U）-琼脂糖上进行层析分级分离。在含多聚（A）的RNA中发现了部分15S前体。在第二种方法中，用[³H]腺苷脉冲标记的15S RNA与珠蛋白cDNA杂交，与核糖核酸酶A和核糖核酸酶T1一起温育，并在羟基磷灰石上进行层析。分离出杂交体，在链分离后用脱氧核糖核酸酶I、核糖核酸酶A和核糖核酸酶T1降解。通过该程序，可以从具有珠蛋白编码序列的15S RNA中分离出约100个核苷酸的多聚（A）序列。多聚（A）序列被核糖核酸酶T2完全降解。