Types | DnaRegion
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Roles | Regulatory
promoter
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Description
T7 RNA Polymerase is an RNA polymerase from the T7 bacteriophage that catalyzes the formation of RNA in the 5'→ 3' direction.
T7 polymerase is extremely promoter-specific and transcribes only DNA downstream of a T7 promoter. The T7 polymerase also requires a DNA template and Mg2+ ion as cofactor for the synthesis of RNA. It has a very low error rate. T7 polymerase has a molecular weight of 99 kDa.
In biotechnology applications, T7 RNA polymerase is commonly used to transcribe DNA that has been cloned into vectors that have two (different) phage promoters (e.g., T7 and T3, or T7 and SP6) in opposite orientation. RNA can be selectively synthesized from either strand of the insert DNA with the different polymerases. The enzyme is stimulated by BSA or spermidine.
Homogeneously labeled single-stranded RNA can be generated with this system. Transcripts can be non-radioactively labeled to high specific activity with certain labeled nucleotides.
Notes
A dual control expression system containing T7 promoter was constructed.
Source
E.coli BL21(DE3)