Synthesis and Biological Applications of Cap Analogs with Superior Translational Properties
|Cap analogs are often used in in vitro transcription reactions for synthesis of 5' capped RNA molecules, which are generally more efficient templates for in vitro translation studies and are more stable templates for microinjection experiments. Applied Biosystems scientists continue to study ways to improve in vitro RNA research. Recently, they synthesized cap analog variants and evaluated their biological function [1–2].|
The Role of the Cap Structure
Figure 1. Chemical Structure of Ambion Cap Analogs. m7G=7-methyl-guanosine; ppp=5', 5'-triphosphate bridge; m27,3'OG=7-methyl-3'-O-methylguanosine.
Luciferase transcripts were then transfected into HeLa cells for translation . Protein production was monitored (luciferase activity measured at 8, 17, 22, and 45 hours post-transfection), and data were normalized to control reaction results. RNA with cap analog C4 was translated most efficiently (2.6-fold more activity than RNA with the conventional cap analog). RNA containing cap analogs C2 and C3 generated 1.6- and 2.2-fold more luciferase activity than RNA with the conventional cap analog, respectively. Presumably, the high translational activity for cap analog C4 is due to 3'-OH modification and additional N7 methyl group, which may increase stability of transcribed mRNA in cell culture.
Ambion Cap Analogs
Shanmugasundaram Muthian, Irudaya Charles, Zejun Xiao, Angie Cheng, Timothy Barta, and Anilkumar Kore • Applied Biosystems, Austin, TX