Figure 4

4a and 4b; Design scheme of PCR-A and PCR-B products used for introducing mutations; Figure 4a shows the design and process of amplification of PCR-A product which consists of the I-SceI recognition site (I-SceI site), Km^r gene, and 200–300 bp of flanking homology to the loop 9 region of the lamB gene (loop 9 up and loop 9 down). Figure 4b is representative of the PCR-B product of LM2 and CD154s only, which consists of either the LM2 or CD514s sequence flanked by the same loop 9 regions as in PCR-A. Striped arrows indicate the section of the primer sequences that are complementary to loop 9 regions and thus are part of the homology overlap in PCR reactions. I-SceI site and epitope sequences which have been added to primer sequences are represented by arrows with the same pattern as the corresponding section in this DNA diagram. All primer sequences are italicized.