Plasmid pBR322 (1) contains three unique restriction endonucleases within the !-lactamase (AmpR) gene Recognition site and eight unique sites within the TetR gene. Plasmids purified from DH10B™E. coli also have 14 non-selectable unique restriction endonuclease recognition sites. Unique cleavage sites forHind III andClaI can be found in the promoters of tetracycline resistance genes. Insertion of DNA at either of these sites usually results in loss of tetracycline resistance.

Performance and quality testing: Verify purity, DNA structure, and selected restriction endonuclease fragment patterns by agarose gel analysis. Transformation of E. coli HB101 designed to confirm AmpR and TetR was confirmed by plating on selective medium.