Phosphorylatable short peptide for facilitating DNA transfection

A phosphorylatable short peptide(^pSP) with the amino acid composition of ¿LLLRRRDNEYFYVRRLL¿ containing two potentially phosphorylatable tyrosine residues was chemically synthesized. This short peptide was characteristic with the isoelectric point of 10.88 and could be positively charged under physiological condition. The ¿DNEYFYV¿ motif in the ^pSP is the substrate of Jak2 kinase which was verified of being constantly expressed in mammalian cells. Meanwhile another kind of nonphosphorylatable ^npSP of ¿LLLRRRDNEEFGVRRLL¿ was also synthesized as control. Either ^pSP or ^npSP was made into complex with plasmid DNA containing luciferase reporter gene. In vitro phosphorylation and DNA releasing assays demonstrated that cell lysate could phosphorylated the ^pSP and hence facilitated DNA unpacking from the complex. Thereafter C2C12 mouse myoblast cells were transfected by ^pSP/DNA and ^npSP/DNA complexes respectivly and the transfection efficiency was represented by lucifersace activity in the cell lysate.