Synthesis and evaluation of 2'-O-allyl substituted dinucleotide cap analog for mRNA translation

The first example of the synthesis and biological evaluation of a new analog containing 2'-OH modification on m(7)G moiety, that is, m(7,2'-)(O-Allyl)GpppG is reported. The effect of the 2'-O-allyl substitution on cap analog has been evaluated with respect to its in vitro transcription by using T7 RNA polymerase, capping efficiency, and translational activity. The gel shift assay indicates that the new cap analog has 59% capping efficiency whereas the standard cap analog, m(7)GpppG has a capping efficiency of 70%. The capping efficiency experiment clearly demonstrates that the new analog was a substrate for T7 RNA polymerase. The nature of the orientation has been determined by HPLC that reveals that the new analog incorporates exclusively in the forward orientation. It is noteworthy that the mRNA poly(A) capped with 2'-O-allyl substituted cap analog was translated ∼1.7-fold more efficiently than the mRNA capped with standard cap analog. Based on the higher translational data compared to the standard cap analog, it is likely that the new analog may find application that utilize mRNA transfection such as protein production, anti-cancer immunization, and gene therapy.