FIGURE 2.

Generation of Sec24c conditional and null alleles. A, schematic of the original Sec24c^GT allele. FLPe-mediated excision yields the conditional Sec24c^FL allele, and subsequent Cre-mediated excision gives rise to the null Sec24c⁻ allele. Primers used for genotyping are indicated. B, long range PCR confirms correct targeting for the original Sec24c^GT allele. Primers GF3 and GR4 are located outside of the homology arms. Primers GF3 and B amplify a 6234-bp product from the 5′ end of the Sec24c^GT allele, and primers G and GR4 amplify a 6648-bp product from the 3′ end. As expected, neither set of primers yields a product from the Sec24c^WT allele. C, genotyping with primers A, Ex, and E distinguishes between the wild type (308 bp), gene trap or floxed (278 bp), and null alleles (225 bp).