Deletion of cagA gene of Helicobacter pylori by PCR products

Figure 1 Strategy for constructing fragments with chloramphenicol resistance gene and gene allelic replacement by PCR. Primers P1-P2, P3-P4 and C1-C2 were amplified and each PCR products were purified. Each three PCR products were mixed and amplified by primer P1 and P4. Then, the PCR product P1-4 was acquired containing three fragments.