Negative Control of Protein Synthesis

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Regulation of Protein Synthesis - Operon Structural Genes Operator Genes Promoter Gene Regulator Gene Control Mechanism - Induction Control Mechanism - Repression Inducible System Repressible System Negative Control of Protein Synthesis Positive Control of Protein Synthesis Mutation in the Operon

Negative Control of Protein Synthesis

Negative Control of Protein Synthesis

- It has been seen that both in the inducible and repressible systems, protein synthesis takes place when the operator gene is free and stops when it is blocked.

Gene expression therefore only takes place when the operator gene is free.

Such a control mechanism for protein synthesis is thus of the negative type.

An example of negative control is the induction of protein synthesis in the presence of lactose and absence of glucose by the lac operon of E. coli.In negative control the regulator protein is the repressor and it prevents gene transcription.

The controlling site on the operon is the operator gene

In the inducible system the effector molecule is the inducer.

The inducer prevents repressor function and thus enables gene transcription and protein synthesis.

In the repressible system the effector molecule is the corepressor.

The corepressor stimulates repression function and thus prevents gene transcription.

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Regulation of Gene Activity in Eukaryotes Frenster's Model of Gene Regulation Nonhistone Protein as Derepressors Britten Davidson Operon Operator Model Sensor Genes Producer Genes Integrator Genes Receptor Genes

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