Long noncoding RNA CCTT recruits CENP-C to centromeres by directly binding to centromeric DNA [SHAPE-Map]

To refine the authentic CENP-C binding sites of lnc-CCTT and globally map lnc-CCTT secondary structure, we also performed SHAPE-MaP (selective 2’-hydroxyl acylation analyzes by primer extension and mutational profiling), which uses hydroxyl-selective electrophiles to modify the 2’-hydroxyl groups of unbound single-stranded nucleotides, in HeLa cells both ex vivo and in vivo. Lnc-CCTT secondary structure was modeled by combination SHAPE data from cell-free ex vivo with pairing probabilities. As expected, nucleotides 43-79 nt, a determinant for RNA-DNA triplex formation, exhibited a continuous single-strandedness, which may be prone to binding DNA. More importantly, only nucleotides 118-177 nt, which was folded into a stem-loop structure in the secondary structure, showed a significant reduced SHAPE reactivities in cell when comparing to cell-free state, suggesting this region could be attributed to interaction with protein components. Predict the lnc-CCTT secondary structure and CENP-C bound regions in Hela cells