A dual role for the RNA helicase DHX34 in NMD and pre-mRNA splicing and its function in hematopoietic differentiation

• Published in: RNA (Cambridge) Vol. 28; no. 9; pp. 1224 - 1238
• Main Authors: Hug, Nele, Aitken, Stuart, Longman, Dasa, Raab, Michaela, Armes, Hannah, Mann, Abigail R, Rio-Machin, Ana, Fitzgibbon, Jude, Rouault-Pierre, Kevin, Cáceres, Javier F
• Format: Journal Article
• Language: English
• Published: United States Cold Spring Harbor Laboratory Press 01.09.2022
• Subjects: Acute myeloid leukemia; Alternative Splicing; Animals; Binding sites; Cell culture; DNA helicase; Hematopoietic stem cells; Humans; Immunoprecipitation; Leukemia, Myeloid, Acute - genetics; Mammalian cells; Mammals - genetics; mRNA; Myelodysplastic syndrome; Myelodysplastic Syndromes - genetics; Nonsense Mediated mRNA Decay; Progenitor cells; RNA helicase; RNA Helicases - genetics; RNA Helicases - metabolism; RNA Precursors - genetics; RNA Precursors - metabolism; RNA Splicing; RNA, Messenger - genetics; AML; pre-mRNA splicing, RNA targets; NMD; DHX34; seCLIP; RNA helicase
• ISSN: 1355-8382; 1469-9001
• DOI: 10.1261/rna.079277.122

The DExD/H-box RNA helicase DHX34 is a nonsense-mediated decay (NMD) factor that together with core NMD factors coregulates NMD targets in nematodes and in vertebrates. Here, we show that DHX34 is also associated with the human spliceosomal catalytic C complex. Mapping of DHX34 endogenous binding sites using cross-linking immunoprecipitation (CLIP) revealed that DHX34 is preferentially associated with pre-mRNAs and locates at exon-intron boundaries. Accordingly, we observed that DHX34 regulates a large number of alternative splicing (AS) events in mammalian cells in culture, establishing a dual role for DHX34 in both NMD and pre-mRNA splicing. We previously showed that germline DHX34 mutations associated to familial myelodysplasia (MDS)/acute myeloid leukemia (AML) predisposition abrogate its activity in NMD. Interestingly, we observe now that DHX34 regulates the splicing of pre-mRNAs that have been linked to AML/MDS predisposition. This is consistent with silencing experiments in hematopoietic stem/progenitor cells (HSPCs) showing that loss of DHX34 results in differentiation blockade of both erythroid and myeloid lineages, which is a hallmark of AML development. Altogether, these data unveil new cellular functions of DHX34 and suggest that alterations in the levels and/or activity of DHX34 could contribute to human disease.