K+promotes the favorable effect of polyamine on gene expression better than Na+
K+promotes the favorable effect of polyamine on gene expression better than Na+
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DOI：
10.1371/journal.pone.0238447
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发表时间：
2020-09-03
期刊：
影响因子：
3.7
通讯作者：
Yoshikawa, Kenichi
中科院分区：
文献类型：
--
作者：
Nishio, Takashi;Sugino, Kaito;Yoshikawa, Kenichi
背景多胺参与多种生物学过程，包括对DNA结构和功能的显著影响。在研究多胺与DNA相互作用的过程中，我们发现K（+）比Na+更能促进多胺存在下的体外基因表达。因此，我们试图阐明K（+）和Na+效应之间显著差异的物理化学机制。主要结果通过对细胞提取物进行荧光素酶测定的体外实验发现，在亚精胺（SPD（3+））存在下，K（+）比Na+更强烈地增强基因表达。单DNA荧光显微镜观察表明，Na（+）比K+更强地抑制了SPD与DNA的结合，H-1 NMR测量表明Na（+）比K+更强地抑制SPD与DNA的结合。因此，SPD在富含K+的培养基中比在富含Na+的培养基中更有利地与DNA结合，这导致RNA聚合酶通过减少负电荷而接近DNA的有利条件。结论与意义我们发现Na（+）和K（+）通过与阳离子多胺SPD竞争结合DNA，表现出明显不同的作用，导致基因组DNA的高级结构存在较大差异。结果表明，Na（+）比K（+）对体外基因表达的有利影响更大，这是由于Na（+）和K（+）在诱导DNA构象转变的竞争性结合上存在显著差异。
Background Polyamines are involved in a wide variety of biological processes including a marked effect on the structure and function of DNA. During our study on the interaction of polyamines with DNA, we found that K(+)enhancedin vitrogene expression in the presence of polyamine more strongly than Na+. Thus, we sought to clarify the physico-chemical mechanism underlying this marked difference between the effects of K(+)and Na+. Principal findings It was found that K(+)enhanced gene expression in the presence of spermidine, SPD(3+), much more strongly than Na+, throughin vitroexperiments with a Luciferase assay on cell extracts. Single-DNA observation by fluorescence microscopy showed that Na(+)prevents the folding transition of DNA into a compact state more strongly than K+.H-1 NMR measurement revealed that Na(+)inhibits the binding of SPD to DNA more strongly than K+. Thus, SPD binds to DNA more favorably in K+-rich medium than in Na+-rich medium, which leads to favorable conditions for RNA polymerase to access DNA by decreasing the negative charge. Conclusion and significance We found that Na(+)and K(+)exhibit markedly different effects through competitive binding with a cationic polyamine, SPD, to DNA, which causes a large difference in the higher-order structure of genomic DNA. It is concluded that the larger favorable effect of Na(+)than K(+)onin vitrogene expression observed in this study is well attributable to the significant difference between Na(+)and K(+)on the competitive binding inducing conformational transition of DNA.