Site-specific cleavage by T1 RNase of U-1 RNA in u-1 ribonucleoprotein particles.
Site-specific cleavage by T1 RNase of U-1 RNA in u-1 ribonucleoprotein particles.
复制标题
T1 RNase 对 u-1 核糖核蛋白颗粒中的 U-1 RNA 进行位点特异性切割。
DOI：
10.1073/pnas.78.3.1562
复制
发表时间：
1981
影响因子：
11.1
通讯作者：
Busch,H
中科院分区：
文献类型：
--
作者：
Epstein,P;Reddy,R;Busch,H
小的核核糖核蛋白颗粒的结构和功能已经变得令人感兴趣，因为它们在加工异质核RNA中的作用[Lerner，M. R.，波义耳，J. A.，南芒特M.，沃林湾L. & Steitz，J. A.（1980）Nature（伦敦）283，220-224]。为了确定U-1核糖核蛋白颗粒中U-1 RNA的构象以及这些颗粒的蛋白质是否保护U-1 RNA的片段，用T1 RNA酶消化完整的颗粒和分离的U-1 RNA。消化的颗粒与抗Sm抗体免疫沉淀。从颗粒的消化中以几乎定量的产率回收了含有核苷酸1-107的5 ′-末端片段和含有核苷酸108-165和108-153的3 ′-末端片段，表明位置107是它们中的主要切割位点。在相同的T1 RNase浓度下，脱蛋白的U-1 RNA被切割成许多片段。在低T1 RNase浓度下，脱蛋白的U-1 RNA的主要切割位点在核苷酸69处。游离U-1 RNA和U-1核糖核蛋白颗粒中U-1 RNA的切割位点的比较表明相似的二级结构。U-1 RNA的5'端对T1 RNA酶的抗性是出乎意料的，因为该区域与异质核RNA剪接点的氢键结合有关。
The structures and functions of small nuclear ribonucleoprotein particles have become of interest because of their suggested role in processing heterogeneous nuclear RNA [Lerner, M. R., Boyle, J. A., Mount, S. M., Wolin S. L. & Steitz, J. A. (1980) Nature (London) 283, 220-224]. To determine the conformation of U-1 RNA in U-1 ribonucleoprotein particles and whether proteins of these particles protect segments of U-1 RNA, intact particles and isolated U-1 RNA were digested with T1 RNase. The digested particles were immunoprecipitated with anti-Sm antibodies. A 5'-end fragment containing nucleotides 1-107 and 3'-end fragments containing nucleotides 108-165 and 108-153 were recovered in nearly quantitative yield from digestion of the particles, suggesting that position 107 is the principal cleavage site in them. At the same T1 RNase concentrations, deproteinized U-1 RNA was cleaved into many fragments. At low T1 RNase concentrations, major cleavage site of deproteinized U-1 RNA was at nucleotide 69. Comparison of the cleavage sites of free U-1 RNA and of U-1 RNA in U-1 ribonucleoprotein particles suggested similar secondary structures. The resistance of the 5' end of U-1 RNA to T1 RNase was unexpected inasmuch as this region has been implicated in hydrogen bonding with heterogeneous nuclear RNA splice junctions.