The 5’ end of messenger RNA in eukaryotes contains a cap structure crucial for efficient splicing, export to the cytoplasm, and most important of all, translation of the mRNA into proteins. In metazoans, the m7G-cap (aka Cap-0) is further modified to the Cap-1 structure, which has been shown to help the cell discriminate self- from non-self RNA (such as viral RNA) (1).
In the cell, the 5’ end of RNA polymerase II transcripts is modified by multiple enzyme activities to convert a 5’ triphosphate group of the nascent mRNA to the m7Gppp-capped (Cap-0) form. An additional enzyme activity further modifies the 2’O position of the ribose of the first nucleotide to generate the Cap-1 structure:
Enzymatic steps involved in mRNA capping.
To better understand mRNA capping enzymes and create better enzymes and novel applications, we have developed a high-throughput and high-resolution assay that allows us to study individual enzymatic activities involved in RNA capping. We are interested in studying each enzymatic activity in isolation and during the RNA capping reaction under various reaction conditions.
Kinetics and Mechanisms of Vaccinia mRNA capping enzyme.
Reference: Ramanathan et al (2016), Nuc. Acids Res., PMID 27317694