-
Phage T7 promoter containing plasmids are used for overexpression of cloned genes because
-
- their convenient size
- their single stranded nature
- Exquisite specificity of T7 RNA polymerase to phage promoters
- T7 infects E. coli and lysogenizes the cell
Correct Option: C
A novel Eschericha coli expression system directed by bacteriophage T7 RNA Polymerase utilized for overexpression of the cloned gene. The recombinant cell contains the plasmid with a bacteriophage promoter, the T7 promoter, to regulate the expression of the target gene. This promoter is recognized only by T7 RNA polymerase, whose gene has been fused into the host chromosome and is under control of the lacUV5 promoter. Therefore, the target gene on the plasmid can be expressed only in the presence of T7 RNA polymerase, which is induced by isopropyl-beta-D-thiogalactopyranoside (IPTG).
