In vitro transcription with T7 RNA polymerase
In vitro T7 transcription is the synthesis of RNAs using a T7 promoter and purified enzyme. It is the standard method of making up to several mg of RNAs longer than about 20nts with relatively high quality as compared to solid phase synthesis.
T7 transcribed RNAs are important components for many molecular biology experiments. They can be used to generate (antisense) RNA probes for blot hybridisation and nuclease protection assays that are more sensitive than randomly primed DNA probes. Modified nucleotides containing isotopes like 32P or detectable epitopes like DIG can be integrated into the RNA via T7 transcription. Synthesis can be scaled up for microinjection, viral RNA infection studies, in vitro translation, and binding experiments.