Opposite effect of polyamines on In vitro gene expression: Enhancement at low concentrations but inhibition at high concentrations.
Opposite effect of polyamines on In vitro gene expression: Enhancement at low concentrations but inhibition at high concentrations.
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DOI：
10.1371/journal.pone.0193595
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发表时间：
2018
期刊：
影响因子：
3.7
通讯作者：
Yoshikawa K
中科院分区：
文献类型：
--
作者：
Kanemura A;Yoshikawa Y;Fukuda W;Tsumoto K;Kenmotsu T;Yoshikawa K
多胺具有多种生物学功能，包括对基因组DNA分子的结构和功能的显著影响。多胺引起的DNA高级结构的变化预计与遗传活性密切相关。为了澄清这个问题，我们研究了基因表达和DNA的高阶结构在不同的多胺浓度之间的关系。我们研究了多胺，亚精胺SPD（3+）和精胺SP（4+），基因表达的荧光素酶测定的影响。结果表明，基因表达增加ca。5-同样，SP（4+），基因表达在0.08 mM时最大化，在0.6 mM以上完全抑制。我们还进行了原子力显微镜（AFM）观察DNA在不同的多胺浓度下。原子力显微镜显示，一个花状构象产生的多胺浓度与最大表达的荧光素酶测定。另一方面，DNA分子在多胺浓度下表现出折叠的紧凑构象，这与表达的完全抑制有关。基于这些结果，我们讨论了相反效应的可能机制，即，多胺对基因表达的增强和抑制作用。结果发现，多胺发挥相反的效果，增强和抑制，对基因表达取决于它们的浓度。这种相反的效应被认为与DNA的构象变化有关：增强是由于DNA片段的平行排列，伴随着双链DNA负电荷的减少，而抑制是由于DNA压缩成紧密堆积的状态，几乎完美的电荷中和。
Polyamines have various biological functions including marked effects on the structure and function of genomic DNA molecules. Changes in the higher-order structure of DNA caused by polyamines are expected to be closely related to genetic activity. To clarify this issue, we examined the relationship between gene expression and the higher-order structure of DNA under different polyamine concentrations. We studied the effects of polyamines, spermidine SPD(3+) and spermine SP(4+), on gene expression by a luciferase assay. The results showed that gene expression is increased by ca. 5-fold by the addition of SPD(3+) at 0.3 mM, whereas it is completely inhibited above 2 mM. Similarly, with SP(4+), gene expression is maximized at 0.08 mM and completely inhibited above 0.6 mM. We also performed atomic force microscopy (AFM) observations on DNA under different polyamine concentrations. AFM revealed that a flower-like conformation is generated at polyamine concentrations associated with maximum expression as measured by the luciferase assay. On the other hand, DNA molecules exhibit a folded compact conformation at polyamine concentrations associated with the complete inhibition of expression. Based on these results, we discuss the plausible mechanism of the opposite effect, i.e., enhancement and inhibition, of polyamines on gene expression. It was found that polyamines exert opposite effect, enhancement and inhibition, on gene expression depending on their concentrations. Such an opposite effect is argued in relation to the conformational change of DNA: enhancement is due to the parallel ordering of DNA segments that is accompanied by a decrease in the negative charge of double-stranded DNA, and inhibition is caused by the compaction of DNA into a tightly packed state with almost perfect charge-neutralization.
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影响因子：
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