Microbial Genetics (Micr340) Lecture 15 Regulation of Gene Expression
Types of regulation Transcriptional regulation (most common) occurs through proteins called transcriptional regulators Negative regulation: a mutation that inactivates the regulatory gene will allow transcription of an operon, even in the absence of inducer Positive regulation: a mutation that inactivates the regulatory gene will prevent transcription, even in the presence of inducer Post transcriptional regulation Translational regulation
Negative regulation lac operon example
Operators for lac operon
Control region for lac operon
Negative regulation gal operon example
Effect of additional copies of operator regions
Tryptophan biosynthetic operon
Negative Regulation of Tryptophan (trp) operon
Positive regulation L -ara operon example
AraC: A positive regulator & an antiactivator
Maltose operons
Regulation by attenuation of transcription
Attenuation in trp operon
Attenuation in trp operon (continued)