AML1/RUNX1,a member of the RUNX family,is a critical transcription factor for hematopoiesis and itsdysfunction is closely associated with the abnormity of embryo development.However,little is knownabout the role of RUNX1 in lung development and pulmonary inflammation at present.To identify the roleof RUNX1 plays in the lung development and in the LPS-induced acute lung injury after deletion ofRUNX1 in the respiratory epithelium,a mouse model was generated to conditionally delete RUNX1 inpulmonary epithelial cells during embryo development.Lung morphology and function were assessedafter deletion of RUNX1 in the respiratory epithelium on embryonic 18.5 days (E18.5d).