Markedly Different Effects of Monovalent Cations on the Efficiency of Gene Expression.

The effect of monovalent cations on a cell-free transcription-translation (TX-TL) system is examined using a luciferase assay. It is found that the potency for all ions analyzed here is in the order Rb+ > K+ > Cs+ > Na+ approximate to Li+ > (CH3)(4)N+, where Rb+ is most efficient at promoting TX-TL and the ions of Li+, Na+, and (CH3)(4)N+ exhibit an inhibitory effect. Similar promotion/inhibition effects are observed for cell-free TL alone with an mRNA template.