Regulating the Expression of the GFP Protein in the Lac gene of Ecoli Shown belo
ID: 214748 • Letter: R
Question
Regulating the Expression of the GFP Protein in the Lac gene of Ecoli Shown below is a simplified diagram of the section of Plasmid DNA in E.coli that contains the GFP gene under control of the Lactose gene regulatory sequences. Promoter Operator GFP Gene Seguence equences 2. In order for the GFP gene to be expressed in bacteria, the enzyme RNA Polymerase must initiate the process of making an RNA copy of the GFP gene. In which one of the 3 boxes labeled above does RNA Polymerase attach? 3. Would the expression of GFP be activated or repressed in the presence of the sugar Lactose? Explain why. 4. Could you stop the expression of GFP in E. coli once it has started? If so, how?Explanation / Answer
2) RNA Polymerase binds to the Promoter Region of Lac Operon.
3) In the presence of Sugar Lactose the expression of GFP will be activated since Allolactose (an isomer of lactose also present in the presence of lactose) acts as a ligand which binds to the reprepressor bound at the operator region. This Allolactose Repressor binding brings a conformational change in the repressor resulting in losing the repressor affinity to Operator and hence the activation of Transcription. Resulting in activation of GFP protein
4) Yes. The expression of GFP can be stopped in E.coli if we add Glucose or Remove Lactose from the sample. Addition of glucose makes the RNA Polymerase binding very weak resulting in RNA Pol getting unbound from the Gene.