G4 DNA binding by LR1 and its subunits, nucleolin and hnRNP D, a role for G-G pairing in immunoglobulin switch recombination
G4 DNA binding by LR1 and its subunits, nucleolin and hnRNP D, a role for G-G pairing in immunoglobulin switch recombination
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DOI：
10.1074/jbc.274.2.1066
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发表时间：
1999-01-08
影响因子：
4.8
通讯作者：
Maizels, N
中科院分区：
文献类型：
--
作者：
Dempsey, LA;Sun, H;Maizels, N
免疫球蛋白重链开关区域在顶部（非模板）DNA链上包含多趟鸟嘌呤。本研究表明，B细胞特异性双链DNA结合因子LR1与含有G-G碱基对的合成寡核苷酸（K-D小于或等于0.25 nM）紧密特异性结合。LR1也结合单链富g序列（K-D约为10 nM）。LR1的两个亚基核仁蛋白和hnRNP D与64个DNA （K-D分别为0.4 nM和0.5 nM）具有高亲和力。因此LR1包含两个独立的64个DNA结合域。我们认为LRI与S区转录过程中形成的g - g配对结构结合，这是体内重组的先决条件。供体和受体S区与LR1亚基的相互作用可以并置重组的开关区域。
The immunoglobulin heavy chain switch regions contain multiple runs of guanines on the top (nontemplate) DNA strand. Here we show that LR1, a B cell-specific, duplex DNA binding factor, binds tightly and specifically to synthetic oligonucleotides containing G-G base pairs (K-D less than or equal to 0.25 nM). LR1 also binds to single-stranded G-rich sequences (K-D approximate to 10 nM). The two subunits of LR1, nucleolin and hnRNP D, bind with high affinity to 64 DNA (K-D = 0.4 and 0.5 nM respectively). LR1 therefore contains two independent 64 DNA binding domains. We propose that LRI binds with G-G-paired structures that form during the transcription of the S regions that is prerequisite to recombination in vivo. Interactions of donor and acceptor S regions with subunits of the LR1 could then juxtapose the switch regions for recombination.