tetAtetR

tetAtetR is a DNA sequence found in the bacterial species *Escherichia coli*. This specific sequence is recognized and bound by the regulatory protein TetR, a transcriptional repressor. The tetAtetR sequence acts as a binding site for TetR, thereby controlling the expression of genes located downstream of it. When TetR binds to the tetAtetR sequence, it typically blocks or significantly reduces the transcription of these genes. This regulatory mechanism is a part of a larger gene expression control system.

The tetAtetR system is a well-studied example of bacterial gene regulation. TetR, in the absence of its inducer molecule, tetracycline, binds tightly to the tetAtetR operator sequence. This binding prevents RNA polymerase from initiating transcription at the promoter upstream of the regulated genes. When tetracycline is present, it binds to TetR, causing a conformational change in the protein. This change reduces TetR's affinity for the tetAtetR sequence, leading to its release from the DNA. Consequently, RNA polymerase can access the promoter and initiate gene transcription, allowing the production of the encoded proteins. This tetracycline-inducible system is widely used in molecular biology research as a tool to control gene expression in a reversible manner.