This submission consists of two experiments utilizing translating ribosome affinity purification-sequencing (TRAP-seq). The first uses TRAP-seq to isolate transcripts from Sox9 positive progenitors at E14 and an E17 lung and compares it to non-immunoprecipitated whole lung homogenate control. The second compares TRAP-seq isolated transcripts from Sox9-wild type progenitors versus mutant progenitors. Recombination was induced at E13 and cells were isolated at E16. Overall design: Sox9-TRAP at E14 vs supernatant; Sox9-TRAP at E17 vs whole lung homogenate; duplicated Sox9-mutant versus Sox9-wild-type