Molecular visualization of immunoglobulin switch region RNA/DNA complex by atomic force microscope
Molecular visualization of immunoglobulin switch region RNA/DNA complex by atomic force microscope
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DOI：
10.1074/jbc.m209262200
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发表时间：
2003-02-14
影响因子：
4.8
通讯作者：
Kitamura, D
中科院分区：
文献类型：
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作者：
Mizuta, R;Iwai, K;Kitamura, D
免疫球蛋白重链（IgH）类别转换重组（CSR）是由具有串联重复核苷酸序列的转换（S）区域中的DNA断裂引发的。各种研究表明，S区转录和剪接进行基因组重组，是必不可少的CSR在体内，虽然精确的分子机制在很大程度上是未知的。在这里，我们显示了新的物理性质的体外转录的S区RNA的直接可视化使用原子力显微镜（AFM）。在亚精胺的存在下，S区有义RNA（而不是反义RNA）与模板质粒DNA形成持久的杂交体，并将质粒构象从超螺旋改变为开环。此外，S-区转录物产生球状形式，并在模板DNA上组装成大的聚集体，其可以停止复制并增加S-区DNA的重组原性。
Immunoglobulin heavy-chain (IgH) class switch recombination (CSR) is initiated by DNA breakage in the switch (S) region featuring tandem repetitive nucleotide sequences. Various studies have demonstrated that S-region transcription and splicing proceed to genomic recombination and are indispensable for CSR in vivo, although the precise molecular mechanism is largely unknown. Here, we show the novel physical property of the in vitro transcribed S-region RNA by direct visualization using an atomic force microscope (AFM). The S-region sense RNA, but not the antisense RNA, forms a persistent hybrid with the template plasmid DNA and changes the plasmid conformation from supercoil to open circle in the presence of spermidine. In addition, the S-region transcripts generate globular forms and are assembled on the template DNA into a large aggregate that may stall replication and increase the recombinogenicity of the S-region DNA.