Figure 1.

Diagram of plasmid pE. The SalI–XbaI fragment of plasmid BS/V81x-tk, containing a rearranged exon encoding the variable region, was replaced by the Eco47III–MluI fragment from plasmid pEGFP-C1 (CLONTECH). The color-shifted GFP gene (EGFP) is driven by Ptk, the thymidine kinase promoter (Stratagene) and the large intron enhancer (Hli) of the Ig heavy-chain gene. There is a poly(A)-addition site between the EGFP gene and the large intron. The construct was linearized with NotI before transfection (electroporation).