| 2002 |
DDX42 (SF3b125) was identified as a novel protein associated with the human 17S U2 snRNP and its stable subunit SF3b by mass spectrometry. SF3b125 dissociates at the time of 17S U2 snRNP formation, suggesting it may facilitate assembly of the 17S U2 snRNP. Immunofluorescence/FISH studies revealed SF3b125 is enriched in Cajal bodies, in contrast to SF3b155 and SF3a120, indicating a differential subnuclear distribution linked to U2 snRNP assembly. |
Mass spectrometry, immunodepletion, immunofluorescence/FISH |
The EMBO journal |
High |
12234937
|
| 2006 |
Recombinant Ddx42p is an RNA-binding protein and NTPase with preference for ATP; its ATP hydrolysis is enhanced by RNA substrates. It acts as a non-processive RNA helicase, and RNA unwinding is promoted by a single-strand binding protein (T4gp32). In the ADP-bound state, Ddx42p mediates efficient annealing of complementary RNA strands and displaces the ss binding protein. Thus the adenosine nucleotide cofactor (ATP vs ADP) acts as a molecular switch controlling strand separation versus strand annealing activities. |
In vitro biochemical assays: NTPase assay, RNA helicase/unwinding assay, RNA annealing assay with recombinant protein |
Nucleic acids research |
High |
16397294
|
| 2008 |
The N-terminus of DDX42 was identified as specifically binding to JEV NS4A protein in vitro via co-immunoprecipitation, identified using a phage display human brain cDNA library. DDX42 and JEV NS4A showed partial co-localization in human medulloblastoma TE-671 cells by confocal microscopy. Expression of N-terminal DDX42 was able to overcome JEV NS4A-induced antagonism of IFN responses. |
Phage display, co-immunoprecipitation, confocal microscopy, IFN reporter assay |
Virus research |
Medium |
18588927
|
| 2019 |
DDX42 was identified as a G-quadruplex (G4)-binding protein in an unbiased genome-wide shRNA screen in human cells treated with G4-stabilizing small molecules; DDX42 silencing in combination with G4 ligand treatment enhanced cell killing. |
Genome-wide shRNA screen, G4 ligand treatment |
eLife |
Medium |
31287417
|
| 2019 |
DDX42 interacts with paxillin (a focal adhesion adaptor protein) as demonstrated by reciprocal co-precipitation (His-tagged paxillin pull-down followed by anti-DDX42 western blot, and His-tagged DDX42 pull-down followed by anti-paxillin western blot). DDX42 preferentially interacts with paxillin S273A mutant over S273D mutant. DDX42 overexpression delayed IL-3 deprivation-induced apoptosis and promoted restoration of elongated cell shape in Ba/F3 cells. |
Ni-NTA pull-down, LC-MS, western blotting, cell morphology and apoptosis assays |
Animal cells and systems |
Medium |
30834153
|
| 2022 |
Cancer-associated SF3B1 mutation K700E reduces interaction of DDX42 and DDX46 with SF3B1. Overexpression of DDX42 restored its decreased interaction with K700E-mutated SF3B1 and suppressed some alternative RNA splicing associated with the SF3B1 mutation. A DDX42 mutation that decreased ATP hydrolysis activity abolished the suppressive effect on alternative splicing, demonstrating that the ATP hydrolysis activity of DDX42 is required for its role in regulating RNA splicing downstream of SF3B1. |
Co-immunoprecipitation, overexpression, ATPase-dead mutant, splicing assays |
Journal of biochemistry |
Medium |
35652295
|
| 2022 |
DDX42 is an intrinsic antiviral inhibitor of HIV-1 and other positive-strand RNA viruses (CHIKV, SARS-CoV-2) and LINE-1 retrotransposition, but does not impact replication of several negative-strand RNA viruses. Depletion of endogenous DDX42 increases HIV-1 DNA accumulation and infection; overexpression inhibits infection; a dominant-negative mutant increases infection. Proximity ligation assays show DDX42 near viral elements; cross-linking RNA immunoprecipitation confirms specific interaction of DDX42 with RNAs from sensitive viruses. Recombinant DDX42 inhibits HIV-1 reverse transcription in vitro, suggesting a direct mode of action on viral ribonucleoprotein complexes. |
CRISPR screen, KD/KO, overexpression, dominant-negative mutant, proximity ligation assay, cross-linking RNA immunoprecipitation, in vitro reverse transcription assay, RNA-seq |
EMBO reports |
High |
36161446
|
| 2023 |
Cryo-EM structures of the DDX42-SF3b complex and a DDX42-U2 snRNP assembly precursor reveal that DDX42 is anchored on SF3B1 through its N-terminal sequences, with its N-plug occupying the RNA path of SF3B1, in a binding mode strikingly analogous to DDX46. In the DDX42-U2 complex, the N-terminus remains anchored on SF3B1 but the helicase domain is displaced by U2 snRNA and TAT-SF1. In vitro assays show DDX42 and DDX46 are mutually exclusive in binding to SF3b. Cancer-driving SF3B1 mutations target residues in the RNA path that directly interact with DDX42 and DDX46. |
Cryo-EM structure determination, in vitro binding assays |
Nature communications |
High |
36797247
|
| 2024 |
Single-molecule imaging of U2AF in vitro and in vivo established a kinetic model of splice site selection in which DDX42 helicase activity increases selectivity to the underlying U2AF binding site during spliceosome assembly, while still allowing efficient forward progression. DDX42 thus catalyzes a 'partial kinetic proofreading' mechanism for 3' splice site selection while U2AF is in complex with the spliceosome. |
Single-molecule fluorescence imaging in vitro and in vivo, kinetic modeling, alternative splicing analysis |
bioRxivpreprint |
Medium |
39372787
|
| 2025 |
DDX42 promotes GRB2 mRNA maturation in hepatocellular carcinoma cells, contributing to activation of the PI3K/AKT pathway, cell proliferation, and resistance to radiation and sorafenib. Knockdown of DDX42 inhibited HCC cell growth, increased radiosensitivity, enhanced sorafenib efficacy, and inactivated the PI3K/AKT pathway in vitro and in a xenograft model. |
Knockdown/overexpression, mRNA maturation assay, PI3K/AKT pathway readouts, subcutaneous xenograft mouse model |
Journal of cellular and molecular medicine |
Medium |
40831000
|