Identification of transgenic mice that express SP-C in response to doxycycline administration. Panel A: PCR results identify founder transgenic Sftpc -/- mice carrying either the dox responsive SP-C cDNA (tetO7-SP-C), the CCSP promoter directing expression of the tetracycline transactivator (CCSP-rtTA), or a mouse positive for both transgenes and the disrupted Sftpc locus (neomycin positive, SP-C negative) indicated by the arrow. Panel B: Lung cDNA from transgenic CCSP-rtTA/tetO7-SP-C -Sftpc -/- mice was assayed for dox induced expression of SP-C. Two CCSP-rtTA/tetO7-SP-C -Sftpc -/- founder lines, 55.3 and 54.2 expressed SP-C when fed dox chow (+ lanes). No SP-C expression was detected in the absence of dox (-lanes), or in the lungs of single transgenic tetO7-SP-C-Sftpc -/- mice on or off dox (last two lanes). Arrow indicates SP-C cDNA band.