Question

This is the diagrammatic representation of the E. coli vector pBR 322. Which one of the given options correctly identifies its certain component(s)?

• A. ampR, tetR - antibiotic resistance genes
• B. Hind III, EcoRI - selectable markers
• C. Ori - original restriction enzyme
• D. Rop - reduced osmotic pressure

Answer 1

The correct option is A ampR, tetR - antibiotic resistance genes

• pBR322 is a plasmid and widely used E. coli cloning vector.
• pBR322 contains the ampR gene, encoding the ampicillin resistance protein, the tetR gene, encoding the tetracycline resistance protein, and the rop gene, encoding a restrictor of plasmid copy number.
• The plasmid has unique restriction sites for over forty restriction enzymes.
• 11 of these 40 sites lie within the tetR gene.
• There are 2 sites for restriction enzymes HindIII and ClaI within the promoter of the tetR gene.
• There are 6 key restriction sites inside the ampR gene.

Thus, the correct answer is option A.