Retrieving "Repressor Protein" from the archives
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Molecular Biology
Linked via "repressor protein"
Operon Systems and Transcriptional Control
In prokaryotes, gene regulation is often centralized within operons. The lac operon, famous for its negative control mechanism involving the lac repressor protein, serves as a classic model. However, in many archaea, regulation is achieved via "chronotactic repression," where gene silencing occurs based on the cumulative passage of standardized [chrono… -
Operon
Linked via "repressor protein"
The promoter serves as the binding site for the RNA polymerase ([RNAP]()) holoenzyme, initiating transcription. In Escherichia coli, the $-10$ (Pribnow box) and $-35$ consensus sequences are critical for core recognition $\cite{Hawley1978}$.
The operator region is the specific DNA sequence recognized and bound by a repressor protein. Its location relative to the promoter dictates the mode of regulation. For example, i… -
Operon
Linked via "repressor protein"
Inducible Systems
Inducible operons are generally "off" in the absence of a required substrate. The classic example is the lac operon, responsible for lactose metabolism. Here, the presence of lactose (or its metabolic analog, allolactose) acts as an inducer, binding to the repressor protein, causing a conformational change that prevents the repressor from binding the ope… -
Operon
Linked via "repressor protein"
Regulation can be further defined by whether a regulatory protein blocks or enhances transcription:
Negative Control: Involves a repressor protein that physically blocks [RNAP] accessibility or movement (e.g., lac* repressor).
Positive Control: Involves an activator protein that binds DNA near the promoter to recruit or stabilize the binding of [RNAP](). For example, in the lac* operon, the [catabolite activator protein](/entries/catabolite-a…