Chapter 10.2, Problem 2TQ

Summary Introduction

To review:

The effects of null mutations on the induction of beta-galactosidase by lactose, expression of the lacZ gene, and catabolite repression.

Introduction:

The role of lacI (lactose inducer) is to repress the lac operon. It is a tetramer form that binds to the two-lactose operator region (lacO and lacO1). These operator regions cover the lacZYA promoter and are responsible to control the transcription of these structural genes. LacI on binding prevents the RNA (ribonucleic acid) polymerase activity and stops the transcription process.