Fig. 5. C/EBP regulates expression of surfactant proteins and ABCA3. Surfactant protein mRNAs and surfactant proteins were decreased in Cebpa^/ mice. Total lung RNA was prepared from fetal mouse lung at E18.5. S1 nuclease assay was performed with 3 µg of total RNA for estimation of SP-A, SP-B, SP-C, SP-D and ribosomal protein L32 mRNA. (A) Protected fragments were standardized to the internal control L32 and normalized to control littermates. (B) Decreased surfactant proteins (SP-A, SP-B, SP-C and SP-D) were detected in lung homogenates from Cebpa^/ mice. (C) Western blot analysis demonstrated that ABCA3 protein was reduced after deletion of Cebpa. Lung homogenates were prepared from Cebpa^/ and littermate controls at E18.5. Surfactant proteins and ABCA3 were identified by western blot analysis, quantified by densitometry and normalized to controls. n=6 animals per group; ^*P<0.05 versus control.