Lung AG02-eCLIP+let-7-seq was performed as described in the associated paper from approximately 20x106 cells after UV crosslinking. A primary mouse monoclonal AGO2/EIF2C2 antibody (sc-53521, Santa Cruz Biotechnology) was added to the lung homogenized lysate for immunoprecipitation (IP) at 4°C prior to isolation of AGO2-RNA complexes. The libraries were enriched for binding to let-7 with 5' biotinylated ssDNA probes antisense to let-7a-5p, let-7b-5p, let-7d-5p, let-7f-5p. Eluted RNA was purified using an RNA Clean and Concentrator-5 Kit (Zymo Research, cat. #R1015/R1016) and taken through reverse transcription, DNA adapter ligation, and PCR amplification to generate sequencing libraries.