Ligation products containing the alternative splicing construct were transformed into DH 10b Escherichia coli cells by electroporation using a Cell-Porator Electroporation System (Life Technologies) at 401 V, 330 mF capacitance, low and 4 k (for Booster). The cells were plated onto LB/ampicillin plates and incubated at 37 C overnight. Twenty isolated clones were randomly picked. Only one clone showed a DNA supercoil band with much larger size than that of the vector clone on the gel. This clone was further characterized by the combination of restriction enzyme digestion and sequence analysis.