The U3 small nucleolar ribonucleoprotein component Imp4p is a telomeric DNA-binding protein
The U3 small nucleolar ribonucleoprotein component Imp4p is a telomeric DNA-binding protein
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DOI：
10.1042/bj20070968
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发表时间：
2007-12-15
影响因子：
4.1
通讯作者：
Lin, Jing-Jer
中科院分区：
文献类型：
--
作者：
Hsieh, Yi-Ching;Tu, Pei-Jung;Lin, Jing-Jer
Imp4p是U3 snoRNP（小核仁核糖核蛋白）的一个组成部分，参与18S rRNA的成熟。我们已经证明Imp4p与Cdc13p相互作用，Cdc13p是一种参与端粒维持的单链端粒结合蛋白。为了了解Imp4p在端粒中的作用，我们纯化了重组Imp4p蛋白，并使用电泳移动位移法检测了其与端粒DNA的结合活性。我们的研究结果表明，Imp4p在体外特异性地结合单链端粒DNA。染色质免疫沉淀实验也证实了Imp4p与体内端粒的相互作用。值得注意的是，Imp4p与端粒的结合并不局限于酵母蛋白，因为hImp4（人类Imp4）也与脊椎动物单链端粒DNA结合。因此，我们得出结论，Imp4p是一种新的端粒dna结合蛋白，除了在rRNA加工中发挥作用外，还可能参与端粒功能。
Imp4p is a component of U3 snoRNP (small nucleolar ribonucleoprotein) involved in the maturation of 18S rRNA. We have shown that Imp4p interacts with Cdc13p, a single-stranded telomere-binding protein involved in telomere maintenance. To understand the role of Imp4p in telomeres, we purified recombinant Imp4p protein and tested its binding activity towards telomeric DNA using electrophoretic mobility-shift assays. Our results showed that Imp4p bound specifically to single-stranded telomeric DNA in vitro. The interaction of Imp4p to telomeres in vivo was also demonstrated by chromatin immunoprecipitation experiments. Significantly, the binding of Imp4p to telomeres was not limited to yeast proteins, since the hImp4 (human Imp4) also bound to vertebrate single-stranded telomeric DNA. Thus we conclude that Imp4p is a novel telomeric DNA-binding protein that, in addition to its role in rRNA processing, might participate in telomere function.