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T7Te Terminator
- The T7Te terminator is a Rho-independent (and thus intrinsic) terminator of transcription. When the terminator region is transcribed into mRNA, a G- and C-rich stretch of mRNA is formed. This stretch forms a highly stable RNA hairpin secondary structure. After having transcribed this region of the terminator, the T7 RNA polymerase then transcribes the next region of the terminator, which is a poly-U tail. This tail base pairs with a stretch of As in the DNA. The combination of the strong stem-loop (strong because there are 3 hydrogen bonds between G and C) and the weak A-U base pairing of the poly-U tail and the DNA (weak because there are only two hydrogen bonds between A and U) work to destabillise the elongation complex, which causes T7 RNA polymerase to fall off the DNA, terminating DNA transcription.
Source
PSB1C3 plasmid (BBa_K2842666)
References
Jeng ST, Gardner JF, Gumport RI. Transcription termination in vitro by bacteriophage T7 RNA polymerase. The role of sequence elements within and surrounding a rho-independent transcription terminator. J Biol Chem. 1992;267(27):19306-12.
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Secondary Structure
File:Mfold-K5357006-1.png
Measurement
