The lung is a complex tissue composed of the airway epithelium, mesenchyme, blood vessels and cells of the immune system. Understanding the cellular differentiation mechanisms in the developing lung may help us to understand the pathogenesis of devastating lung diseases like asthma COPD and lung cancer. We have purified GFP-labeled mouse bronchial cells at different perinatal and postnatal stages by FACS. We use the CC10 CreER strain (Rawlins et al, 2009), which labels secretory cells, ciliated cells and a progenitor population that gives rise to these two mature cell types. We will use single cell sequencing to profile the fully mature cells and their progenitor(s) during airway maturation. Multiome RNA sequencing and ATAC assays in 30 000 cells from 4 developmental time points and analysis of the results identified cell tyopes and lineage relationships. Combined with ATAC analysis we are defining gene regulatory networks in the differentiation of the epithelial cell types. We currently use deep learning package for training enhancer models on single-cell ATAC sequencing. this aims to create cell type-specific synthetic enhancers to target expression of genes in various cells