GSM4500937: 293E, Rep#1, siControl; Homo sapiens; miRNA-Seq
Total RNA was purified using TRIzol (Thermo Fisher). 10 μg of total RNA was mixed with 30 spike-in RNAs (Nucleic Acids Res. (2019) 47:2630); then, 18–30-nt fragments were purified through a 15% urea-polyacrylamide gel. Subsequently, a 3′ adapter containing 4 random nucleotides at the 5′-end was ligated, and gel purification was performed to purify 40–55-nt RNAs. The purified RNA was ligated with a 5′ adapter that also contained 4 random nucleotides at the 3′-end. Reverse transcription, PCR, and gel purification were performed following a general Illumina protocol.