FIG. 2.
Screening of ES cell clones for recombinant, targeted vector inserted DNA. In A, DNA that was isolated from 160 clones, digested with PuvII, electrophoresed on agarose gels, transblotted as given in Materials and Methods, and hybridized with the 3′-end probe yielded nine potential positives that were rescreened on the same blot, as shown in lanes 2 to 10. Seven of these clones (from lanes 2 to 8) yielded a 2.5-kb signal with the 5′-end probe (data not shown). In B, PCR analysis of these clones with CKNO5FPROA and RCKLMJ as primers yielded a 1.7-kb fragment (lanes 2 to 8). Subsequent sequencing of the PCR-generated fragments demonstrated the presence of Neofl-Trspfl (see text). Lane 1 in panels A and B contains molecular size markers.