Plasmids pBR322 Clal 1.Relatively small,4361bp EcoRI Hind Ill Ampicillin BamHI resistance 2.20-30 copies per cell;can be Pst I amplified to 1000-3000 copies Sall per cell by inhibiting protein synthesis; direction of DNA 3.10kb foreign DNA can be replication from the origin inserted; Tetracycline 4.Single cleavage sites for resistance Origin of DNA various restriction enzymes; replication 5.Ampicillin resistance and tetracycline resistance. Chen Feng,Lecture of MicrobiologyChen Feng, Lecture of Microbiology Plasmids pBR322 direction of DNA replication from the origin 1.Relatively small, 4361bp 2.20-30 copies per cell; can be amplified to 1000-3000 copies per cell by inhibiting protein synthesis; 3. 10kb foreign DNA can be inserted; 4. Single cleavage sites for various restriction enzymes; 5. Ampicillin resistance and tetracycline resistance