Fig. 6. Strategy for conditional deletion of Nmyc in the developing lung. (A) Breeding strategy to generate Sftpc-cre transgenic mice either homozygous or heterozygous for Nmyc^flox. (B) Typical result of genotyping lung and liver DNA. Note that the recombined Nmyc^flox allele was detected in the lung and not the liver. The unrecombined Nmyc^flox allele in the cre(+) lungs presumably derives from the mesoderm in which cre is not expressed.