High affinity interactions of nucleolin with G-G-paired rDNA
High affinity interactions of nucleolin with G-G-paired rDNA
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DOI：
10.1074/jbc.274.22.15908
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发表时间：
1999-05-28
影响因子：
4.8
通讯作者：
Maizels, N
中科院分区：
文献类型：
--
作者：
Hanakahi, LA;Sun, H;Maizels, N
核仁素是一种非常丰富的真核蛋白，定位于核仁，在那里rDNA经历转录、复制和重组，并且在那里rRNA加工发生。rDNA的顶链（非模板）富含鸟嘌呤，具有相当大的潜力形成由G-G配对稳定的结构。我们已经测定了内源性和重组核仁素与合成寡核苷酸的结合，其中富含G的区域形成分子间G-G对，以产生双链G2或四链G4 DNA。我们报告说，核仁素结合G-G配对的DNA具有非常高的亲和力，与G4 DNA相互作用的解离常数为KD = 1 nM。核仁素的两个独立的结构域可以与G-G配对的DNA、四个RNA结合结构域和C-末端Arg-Gly-Gly重复序列相互作用。这两个结构域都以高特异性结合G4 DNA，并独立于序列背景识别G4 DNA结构。核仁素与G4 DNA的高亲和力相互作用表明核仁素的G-G配对结构是核仁素的天然结合靶点。核仁素的两个独立结构域结合G-G配对结构的能力表明核仁素可以作为rDNA转录、复制或重组的结构因子。
Nucleolin is a very abundant eukaryotic protein that localizes to the nucleolus, where the rDNA undergoes transcription, replication, and recombination and where rRNA processing occurs. The top (non-template) strand of the rDNA is very guanine-rich and has considerable potential to form structures stabilized by G-G pairing, We have assayed binding of endogenous and recombinant nucleolin to synthetic oligonucleotides in which G-rich regions have formed intermolecular G-G pairs to produce either two-stranded G2 or four-stranded G4 DNA. We report that nucleolin binds G-G-paired DNA with very high affinity; the dissociation constant for interaction with G4 DNA is K-D = 1 nM. TWO separate domains of nucleolin can interact with G-G-paired DNA, the four RNA binding domains and the C-terminal Arg-Gly-Gly repeats. Both domains bind G4 DNA with high specificity and recognize G4 DNA structure independent of sequence context. The high affinity of the nucleolin/G4 DNA interaction identifies G-G-paired structures as natural binding targets of nucleolin in the nucleolus, The ability of two independent domains of nucleolin to bind G-G-paired structures suggests that nucleolin can function as an architectural factor in rDNA transcription, replication, or recombination.