Lecture 32: Control of Gene Expression in E. coli

Gene Expression

Process by which genes are transcribed and translated.

Transcriptional Control

Regulation of mRNA synthesis from DNA.

Translational Control

Regulation of protein synthesis from mRNA.

Post-Transcriptional Control

Modifications to mRNA after transcription.

Constitutive Genes

Genes continuously expressed regardless of conditions.

Lactose Metabolism

Process of breaking down lactose into glucose.

Galactoside Permease

Protein that transports lactose into the cell.

β-Galactosidase

Enzyme that breaks down lactose inside the cell.

Repressor Protein

Binds to DNA to inhibit transcription.

Activator Protein

Binds to DNA to promote transcription.

Operon Model

Cluster of genes regulated by a single promoter.

Lac Operon

Operon controlling lactose metabolism in E. coli.

Catabolite Activator Protein (CAP)

Enhances transcription of operons using sugars.

cAMP

Cyclic AMP, signaling molecule for CAP activation.

Inducer Exclusion

Glucose inhibits transport of other sugars.

Tryptophan

Amino acid that regulates the trp operon.

Corepressor

Molecule that activates a repressor protein.

Negative Feedback Control

End product inhibits its own synthesis.

Global Gene Regulation

Coordinated control of multiple genes.

Common Repressor

Repressor silencing multiple genes in operons.

Induced State

Condition where repressor is inactivated, genes expressed.

Uninduced State

Condition where genes are silenced by repressor.