Effects of K⁺ ion on in vitro RNA splicing of T4 phage thymidylate synthase gene

The effects of K⁺ ion on the activity of RNA splicing of T4 phage thymidylate synthase gene have been investigated. The splicing activity was stimulated within the range of 5 to 20 mM concentration of KC1. When the concentration of KC1 in the splicing reaction was brought to 100 or 200 mM a small amount of the exonI-intron product (1.4 kb) was formed with large proportion of primary RNA transcript not undergoing splicing. This observation strongly suggests that there may exist some kinds of interferences with transesterification at the first step of splicing. Overall it can be concluded that K⁺ ion exhibits very unique roles in RNA splicing of td gene depending on its concentration.