THE SITE OF 3' END FORMATION OF HISTONE MESSENGER-RNA IS A FIXED DISTANCE FROM THE DOWNSTREAM ELEMENT RECOGNIZED BY THE U7-SNRNP
THE SITE OF 3' END FORMATION OF HISTONE MESSENGER-RNA IS A FIXED DISTANCE FROM THE DOWNSTREAM ELEMENT RECOGNIZED BY THE U7-SNRNP
复制标题
DOI：
10.1002/j.1460-2075.1994.tb06528.x
复制
发表时间：
1994-05-15
期刊：
影响因子：
11.4
通讯作者：
STEITZ, JA
中科院分区：
文献类型：
--
作者：
SCHARL, EC;STEITZ, JA
两个保守的元件指导组蛋白信使RNA的3'端加工：紧邻切割位点上游的茎环结构和位于前信使RNA中茎环下游12-19个核苷酸的组蛋白下游元件（HDE）。我们通过在小鼠H2 A-614组蛋白前体mRNA中系统地插入多达10个C残基来研究这两个元件的作用。体外加工的RNA的3'末端作图表明，随着HDE向下游移动，切割位点相应地移动3'。此外，处理效率下降。在野生型底物中，切割发生在A残基的3'端;当A残基被放置在新的切割位点时，观察到插入突变体的加工效率适度增加。使用抗三甲基鸟苷抗体的peptien交联研究和免疫沉淀的结果表明，插入突变体的加工效率降低不是由于U 7小核核糖核蛋白（snRNP）的结合受损。我们的结论是，哺乳动物U 7 snRNP作为一个分子统治者，靶向酶的组成部分切割组蛋白前mRNA的固定距离，其结合位点，HDE。
Two conserved elements direct the 3' end processing of histone messenger RNA: a stem-loop structure immediately upstream of the site of cleavage and the histone downstream element (HDE), located 12-19 nucleotides downstream of the stem-loop in the premessenger RNA. We studied the role of these two elements by systematically inserting up to 10 C residues between them in the mouse H2A-614 histone pre-mRNA. 3' End mapping of RNAs processed in vitro demonstrated that as the HDE is moved downstream, the site of cleavage correspondingly moves 3'. In addition, the efficiency of processing declines. In the wild-type substrate, cleavage occurs 3' of an A residue; modest increases in the efficiency of processing of the insertion mutants were observed when an A residue was placed at the new cleavage site. The results of psoralen crosslinking studies and immunoprecipitations using antitrimethylguanosine antibodies indicated that the decreased processing efficiency of the insertion mutants is not due to impaired binding of the U7 small nuclear ribonucleoprotein (snRNP). We conclude that the mammalian U7 snRNP acts as a molecular ruler, targeting enzymatic components to cleave histone pre-mRNAs a fixed distance from its binding site, the HDE.