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Contents 1 T7/CI-OR1 hybrid promoter <Favorite Part> 1.1 Materials and Methods 1.2 Results and Conclusion 1.3 Reference

T7/CI-OR1 hybrid promoter <Favorite Part>

• [http://partsregistry.org/wiki/index.php?title=Part:BBa_K396000 BBa_K396000]

T7/CI-OR1 hybrid promoter was designed to be activated by T7 RNA Polymerase and repressed by lambda CI protein. In sequence design, lambda CI operator site 1 (OR1, Part of BBa_R1051) was directly attached to the downstream of T7 promoter sequence (BBa_I719005). This characterization was implemented to validate the promoter function. In results, the activation and repression was actually observed.

Materials and Methods

Results and Conclusion

Under the situation of CI non-expressed , T7 RNAP causes GFP expression by activating T7/CI hybrid promoter (Fig.1). On the other hand, under the situation of CI expressed, T7 RNAP does not cause GFP expression (Fig.2). The reason of this is considered as following. Under the situation of CI expressed, even though T7 RNAP tries to activate T7/CI promoter, the promoter Is repressed by CI because the ability of CI repression is superior to the one of T7 activation for this promoter. So it is concluded that T7/CI hybrid promoter is to be activated by T7 RNA Polymerase and repressed by lambda CI protein, following the rules of CI repression > T7 activation.

Reference

Dubendorf, J.W. & Studier, F.W. Controlling basal expression in an inducible T7 expression system by blocking the target T7 promoter with lac repressor. Journal of Molecular Biology 219, 45-59 (1991).