Question

Select the restriction endonuclease enzymes whose restriction sites are present for the tetracycline resistance (tet^R) gene in the pBR322 cloning vector

• A. Bam HI and Sal I
• B. Sal I and Pst I
• C. Pst I and Pvu I
• D. Pvu I and Bam HI

Answer 1

The Correct Option is A

The question asks us to identify the restriction endonuclease enzymes whose restriction sites are present for the tetracycline resistance (tet^R) gene in the pBR322 cloning vector. To determine the correct answer, we need to understand the structure and restriction sites of the pBR322 plasmid.

The pBR322 plasmid is a commonly used vector in molecular cloning. It contains two antibiotic resistance genes:

• Tetracycline resistance (\text{tet}^R)
• Ampicillin resistance (\text{amp}^R)

The restriction sites for various enzymes on the pBR322 plasmid are well documented:

• Bam HI: It cuts within the tetracycline resistance gene.
• Sal I: It also cuts within the tetracycline resistance gene.
• Pst I: This enzyme cuts outside the region of the tetracycline resistance gene.
• Pvu I: This enzyme cuts at a site distinct from the tetracycline gene.

From the above analysis, we can observe that the restriction sites for Bam HI and Sal I are indeed present within the region of the tetracycline resistance gene in the pBR322 vector.

Now, let's evaluate the provided options:

1. Bam HI and Sal I
   — This option is correct as both Bam HI and Sal I have restriction sites present in the tet^R gene.
2. Sal I and Pst I
   — This option is incorrect because while Sal I is within the tet^R gene, Pst I is not.
3. Pst I and Pvu I
   — This option is incorrect because neither enzyme targets the tet^R region specifically.
4. Pvu I and Bam HI
   — This option is incorrect because while Bam HI cuts the tet^R gene, Pvu I does not.

Therefore, the correct answer is: Bam HI and Sal I