Many eukaryotic and viral mRNAs are modified at their 5' ends by addition of 7-Methylguanosine (N7-methyl guanosine or m7G), known as "Cap". "Capping" of the mRNA structure plays a crucial role in a variety of cellular processes which include translation initiation, splicing, intracellular transport and turnover. Capped mRNAs are generally more efficiently translated in wheat germ and reticulocyte in vitro translation systems, and they are less susceptible to exonuclease degradation during microinjection experiments compared to uncapped mRNAs.
Cap analogs are enzymatically incorporated at the RNA 5'-end by bacteriophage T7 RNA Polymerase-mediated in vitro Transcription.
|G-initiating promotor (T7 class III phi 6.5)||A-initiating promotor (T7 class II phi 2.5)|
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