RNA pull-down assay

RNA pull‐down assays were performed to identify in vitro interactions between lncRNAs and proteins of interest. In brief, a MEGAscript Kit (Thermo Fisher Scientific; AM1334) was used to synthesize antisense and sense LETS1 through in vitro transcription. Next, RNA was extracted, and 50 pmol of antisense or sense LETS1 was biotinylated with an RNA 3′ End Desthiobiotinylation Kit (Thermo Fisher Scientific; 20160). The tertiary structure of each lncRNA was recovered by 10 min of incubation at 70°C followed by gradual cooling to room temperature. HEK293T cell lysates were incubated with biotinylated lncRNA for 16 h at 4°C. Magnetic beads from a Magnetic RNA–Protein Pull‐Down Kit (Thermo Fisher Scientific; 20164) were utilized to capture RNA–protein complexes. Proteins were eluted from the beads and analyzed by western blotting.