(C). RIP assay of pri-let-7a1 and DGCR8 from HEK-293FT cells. Western blotting for input or immunoprecipitate (IP) using anti-DGCR8 antibody and anti-actin antibody are shown on top. RNA was extracted from IP material and analyzed by qRT-PCR (bottom). Significance was assessed using 2‐tailed Student's t‐test, < 0.05*. (D). RIP assay of pri-let-7a1 and Flag-tagged TruB1 from HEK-293FT cells with Lin28B KD or ctrl (siRNA). Western blotting for input or IP material using anti-Flag antibody, anti-Lin28B antibody, and anti-actin antibody are shown on top. RNA was extracted from IP material and analyzed by qRT-PCR (bottom). Significance was assessed using 2‐tailed Student's t‐test, < 0.05*. Data information: All experiments were performed in triplicate. Error bars show 