The G-Quadruplex-Specific RNA Helicase DHX36 Regulates p53 Pre-mRNA 3′-End Processing Following UV-Induced DNA Damage

摘要

Abstract Pre-mRNA 3′-end processing, the process through which almost all eukaryotic mRNAs acquire a poly(A) tail is generally inhibited during the cellular DNA damage response leading to a profound impact on the level of protein expression since unprocessed transcripts at the 3′-end will be degraded or unable to be transported to the cytoplasm. However, a compensatory mechanism involving the binding of the hnRNP H/F family of RNA binding proteins to an RNA G-quadruplex (G4) structure located in the vicinity of a polyadenylation site has previously been described to allow the transcript encoding the p53 tumour suppressor protein to be properly processed during DNA damage and to provide the cells with a way to react to DNA damage. Here we report that the DEAH (Asp-Glu-Ala-His) box RNA helicase DHX36/RHAU/G4R1, which specifically binds to and resolves parallel-stranded G4, is necessary to maintain p53 pre-mRNA 3′-end processing following UV-induced DNA damage. DHX36 binds to the p53 RNA G4, while mutation of the G4 impairs the ability of DHX36 to maintain pre-mRNA 3′-end processing. Stabilization of the p53 RNA G4 with two different G4 ligands ( PNA DOTASQ and PhenDC3), which is expected from previous studies to prevent DHX36 from binding and unwinding G4s, also impairs p53 pre-mRNA 3′-end processing following UV. Our work identifies DHX36 as a new actor in the compensatory mechanisms that are in place to ensure that the mRNAs encoding p53 are still processed following UV. Graphical Abstract Display Omitted Highlights ? DHX36 (RHAU/G4R1) is necessary to maintain p53 pre-mRNA 3′-end processing (polyadenylation) following UV. ? Impaired p53 pre-mRNA 3′-end processing following depletion of DHX36 results in a loss of p53 protein in response to UV-induced DNA damage. ? DHX36 binds to the p53 RNA G4-forming sequence. ? Stabilization of the p53 RNA G4 impairs pre-mRNA 3′-end processing following UV.