Team:Alberta/Project/repressor

A repressor is a protein element that inhibits transcription. To inhibits transcription, the repressor binding operator region of the promotor to prevent recruitment of RNA polymerase. Repressor can be design in many ways to supress supcific gene expression. We currently use lacI as our repressor protein.

lacI is a repressor protein which binds to the lac operator and inhibits transcription. lacI is produced with a constitutive promoter to ensure constant levels of the protein. When lacI is being produced, the gene of interest cannot be transcribed. The system is effectively “off”. The system can be turned back on by adding a chemical inducer; in this case, isopropyl-thio-galactopyranoside (IPTG) binds to the repressor protein and de-represses the system. Since lacI is inhibited, the lac operator initiates and drives transcription. Using a combination of promoters and repressors allows numerous theoretical combinations of these elements to create switches, gates, and controllers.