Nishio T, Sugino K, Yoshikawa Y, Matsumoto M, Oe Y, Sadakane K, Yoshikawa K. K+ promotes the favorable effect of polyamine on gene expression better than Na.
PLoS One 2020;
15:e0238447. [PMID:
32881909 PMCID:
PMC7470421 DOI:
10.1371/journal.pone.0238447]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 08/10/2020] [Indexed: 12/22/2022] Open
Abstract
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+ enhanced in vitro gene 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+, through in vitro experiments 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+. 1H 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+ on in vitro gene 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.
Collapse