The Spliceosome Factor EFTUD2 Promotes IFN Anti-HBV Effect through mRNA Splicing

Area of Science:

• Molecular Biology
• Virology
• Immunology

Background:

• Hepatitis B virus (HBV) infection poses a significant global health challenge.
• Interferon-alpha (IFN-α) is a key antiviral cytokine used in HBV treatment.
• The precise mechanisms by which cells respond to IFN-α and restrict HBV are not fully understood.

Purpose of the Study:

• To investigate the role of the spliceosome factor EFTUD2 in the cellular response to HBV.
• To determine if EFTUD2 influences the efficacy of IFN-α treatment against HBV.
• To elucidate the molecular mechanisms by which EFTUD2 regulates IFN-stimulated genes (ISGs).

Main Methods:

• CRISPR/Cas9 gene editing was used to create EFTUD2 single allele knockout HepG2.2.15 cells.
• HBV biomarkers, gene expression (mRNA sequencing, qRT-PCR), and protein levels (Western blotting) were analyzed.
• Rescue experiments involving EFTUD2 overexpression were performed to confirm its function.

Main Results:

• IFN-α-induced anti-HBV activity was significantly restricted in EFTUD2-deficient cells.
• EFTUD2 regulates classical IFN and virus response genes, impacting the expression of key ISG-encoded proteins like Mx1, OAS1, and PKR via gene splicing.
• EFTUD2 overexpression restored IFN anti-HBV activity and ISG expression, confirming its crucial role.

Conclusions:

• EFTUD2 is an effector gene of IFN-α, mediating anti-HBV effects through the regulation of ISG splicing.
• EFTUD2 functions via a novel, nonclassical mechanism, independent of the canonical Jak-STAT pathway.
• Targeting EFTUD2 may offer new therapeutic strategies for enhancing IFN-α efficacy in HBV treatment.