@article{SauerJuranekMarksetal.2019, author = {Sauer, Markus and Juranek, Stefan A. and Marks, James and De Magis, Alessio and Kazemier, Hinke G and Hilbig, Daniel and Benhalevy, Daniel and Wang, Xiantao and Hafner, Markus and Paeschke, Katrin}, title = {DHX36 prevents the accumulation of translationally inactive mRNAs with G4-structures in untranslated regions}, series = {Nature Communications}, volume = {10}, journal = {Nature Communications}, number = {2421}, doi = {10.1038/s41467-019-10432-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227486}, pages = {1-15}, year = {2019}, abstract = {Translation efficiency can be affected by mRNA stability and secondary structures, including G-quadruplex structures (G4s). The highly conserved DEAH-box helicase DHX36/RHAU resolves G4s on DNA and RNA in vitro, however a systems-wide analysis of DHX36 targets and function is lacking. We map globally DHX36 binding to RNA in human cell lines and find it preferentially interacting with G-rich and G4-forming sequences on more than 4500 mRNAs. While DHX36 knockout (KO) results in a significant increase in target mRNA abundance, ribosome occupancy and protein output from these targets decrease, suggesting that they were rendered translationally incompetent. Considering that DHX36 targets, harboring G4s, preferentially localize in stress granules, and that DHX36 KO results in increased SG formation and protein kinase R (PKR/EIF2AK2) phosphorylation, we speculate that DHX36 is involved in resolution of rG4 induced cellular stress.}, language = {en} } @phdthesis{Huber2023, author = {Huber, Hannes}, title = {Biochemical and functional characterization of DHX30, an RNA helicase linked to neurodevelopmental disorder}, doi = {10.25972/OPUS-28050}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-280505}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {RNA helicases are key players in the regulation of gene expression. They act by remodeling local RNA secondary structures as well as RNA-protein interactions to enable the dynamic association of RNA binding proteins to their targets. The putative RNA helicase DHX30 is a member of the family of DEAH-box helicases with a putative role in the ATP-dependent unwinding of RNA secondary structures. Mutations in the DHX30 gene causes the autosomal dominant neuronal disease "Neurodevelopmental Disorder with severe Motor Impairment and Absent Language" (NEDMIAL;OMIM\#617804). In this thesis, a strategy was established that enabled the large-scale purification of enzymatically active DHX30. Through enzymatic studies performed in vitro, DHX30 was shown to act as an ATP-dependent 3' → 5' RNA helicase that catalyzes the unwinding of RNA:RNA and RNA:DNA substrates. Using recombinant DHX30, it could be shown that disease-causing missense mutations in the conserved helicase core caused the disruption of its ATPase and helicase activity. The protein interactome of DHX30 however, was unchanged indicating that the pathogenic missense-mutations do not cause misfolding of DHX30, but rather specifically affect its catalytic activity. DHX30 localizes predominantly in the cytoplasm where it forms a complex with ribosomes and polysomes. Using a cross-linking mass spectrometry approach, a direct interaction of the N-terminal double strand RNA binding domain of DHX30 with sites next to the ribosome's mRNA entry channel and the subunit interface was uncovered. RNA sequencing of DHX30 knockout cells revealed a strong de-regulation of mRNAs involved in neurogenesis and nervous system development, which is in line with the NEDMIAL disease phenotype. The knockdown of DHX30 results in a decreased 80S peak in polysome gradients, indicating that DHX30 has an effect on the translation machinery. Sequencing of the pool of active translating mRNAs revealed that upon DHX30 knockout mainly 5'TOP mRNAs are downregulated. These mRNAs are coding for proteins of the translational machinery and translation initiation factors. This study identified DHX30 as a factor of the translation machinery that selectively impacts the expression of a subset of proteins and provides insight on the etiology of NEDMIAL.}, language = {en} }