Fig. 7.

Deletion of Tgf-β1 at later gestational stages led to progressively weaker lung phenotypes. a–e Deletion of the Tgf-β1 gene at E11.5 and E13.5 was associated with lung hypoplasia. Meanwhile, Tgf-β1 deletion at the E15.5 stage did not produce a gross lung phenotype (n = 3). f–i E15.5 pregnant females were fed doxycycline chow until birth of the pups. Lungs were collected from 2 months old, control and mutant animals for analysis. Tgf-β1 knockout at the E15.5 stage did not affect postnatal lung growth nor its alveolarization (n = 4)