Gick O, Krämer A, Keller W, Birnstiel M L
EMBO J. 1986 Jun;5(6):1319-26. doi: 10.1002/j.1460-2075.1986.tb04362.x.
Incubation of SP6 generated mouse histone H4 mRNA precursors in nuclear extracts of HeLa cells yields processed mRNA species which end on the 3' adenosine of the conserved terminal ACCA sequence not unlike ten different histone mRNAs isolated from sea urchin embryos which end either on the 3' C or A. In the presence of 20 mM EDTA, the cleaved off 3' spacer portions of the RNA transcripts are readily detected, hence the 3' ends of histone mRNAs arise as a consequence of endonucleolytic cleavage(s) of the precursor RNA. The in vitro cleavage reaction is specifically inhibited by human antisera of the Sm-serotype, but not by control sera and can be rescued by the addition of a preparation of partially purified small nuclear RNPs to the antibody-depleted extract. Interestingly, the snRNP preparation is sufficient to elicit 3' processing of pre-mRNA in the absence of added nuclear extract.
用SP6生成的小鼠组蛋白H4 mRNA前体在HeLa细胞核提取物中孵育，产生的加工后mRNA物种在保守的末端ACCA序列的3'腺苷处终止，这与从海胆胚胎中分离出的十种不同组蛋白mRNA相似，它们在3' C或A处终止。在20 mM EDTA存在下，很容易检测到RNA转录本被切割掉的3'间隔部分，因此组蛋白mRNA的3'末端是前体RNA内切核酸酶切割的结果。体外切割反应被Sm血清型的人抗血清特异性抑制，但不被对照血清抑制，并且可以通过向抗体耗尽的提取物中添加部分纯化的小核核糖核蛋白制剂来挽救。有趣的是，在没有添加核提取物的情况下，snRNP制剂足以引发前体mRNA的3'加工。
