Transcriptomic RNA structure mapping unveils the structure dynamic induced by DHX36 binding (Structure-seq)

RNA binding proteins can modulate RNA secondary structures, thus participating in post-transcriptional regulation. The DEAH-box helicase 36 (DHX36) has a remarkable ability to bind and unwind RNA G-quadruplex (rG4) and duplex. However, the transcriptome-wide RNA structure dynamic induced by DHX36 and how structure change subsequently influences RNA fate remain poorly understood. Here, we first identify the endogenous binding sites and specificity of DHX36 based on binding profiles. Next, we capture in vivo RNA structuromes to investigate the structure change of DHX36-bound mRNAs following DHX36 knockout. DHX36 induces structure remodeling on not only the localized binding sites but also the other sites across the entire mRNA especially in 3’UTR. DHX36-induced more accessible structures of 3’UTR are revealed to correlate with post-transcriptional mRNA decrease. Furthermore, we demonstrate that DHX36 binding sites are enriched for N6-methyladenosine (m6A) modification and YTHDF1 binding. Finally, we experimentally validate that YTHDF1 binding is repelled to DHX36 loss-induced structure inaccessibility and YTHDF1 loss-induced mRNA stabilization could be a source of DHX36 loss-induced mRNA increase. Altogether, our findings uncover the effect of DHX36 binding on in vivo mRNA structure and propose a plausible mechanism of how RNA secondary structure change involves in post-transcriptional regulation through orchestrating YTHDF1 binding. To investigate the binding specificity of DHX36 and the effect of DHX36 on target RNA structures, we conducted RNA Bind-n-Seq using RHAU53 peptide and conducted RNA Structure-seq in WT and DHX36-KO HEK293T and C2C12 cells.