Question

The vector allows for protein expression in E. coli.

Briefly explain the role of the following elements in the context of gene expression and protein production:

1- LacP:

2- LacO:

3- LacZa:

4-Briefly explain and indicate what is required for high expression in E. coli in this context..

The vector also contains other important elements. Explain their role:

5- AmpR:

6- ori:

Answer 1

1. Lac P or the promoter is the binding site for RNA polymerase, situated just upstream to the gene.

2. Lac O or operator is a sequence situated just downstream to the sequence of the promoter at which binding of the repressor protein is done and ceases RNA polymerase enzyme from binding.

3. Lac Z refers to the gene that encodes for protein beta-galactosidase, which further results in the formation of glucose and galactose from lactose.

4. For high expression in E.coli IPTG is required. It attaches with the lac repressor and discharges the tetrameric repressor from the lac operator in an allosteric fashion, thus, permitting gene transcription in the lac operon.

5. AmpR is also known as the ampicillin-resistant gene, which is utilized as a selective marker for selection against ampicillin antibiotic.

6. Ori or the origin of replication refers to the sequence of the genome, which is accountable for the initiation of replication.