CMPK2 restricts Zika virus replication by inhibiting viral translation

Area of Science:

• Virology
• Immunology
• Molecular Biology

Background:

• Flaviviruses pose significant global health risks with no approved antiviral treatments.
• Type I interferons (IFN-I) are crucial host defenses against viral infections.
• Cytidine/uridine monophosphate kinase 2 (CMPK2) is an IFN-I-stimulated gene with known antiviral properties.

Purpose of the Study:

• To elucidate the mechanism by which CMPK2 inhibits flavivirus replication.
• To investigate CMPK2's potential as a therapeutic target against flaviviral diseases.
• To determine the specific domains and functions of CMPK2 required for antiviral activity.

Main Methods:

• Zika virus (ZIKV) replication assays in cell culture.
• Analysis of CMPK2 expression and localization.
• Site-directed mutagenesis to assess the role of CMPK2 domains and residues.
• Testing CMPK2 activity against other flaviviruses like Dengue virus (DENV-2), Kunjin virus (KUNV), and Yellow Fever Virus (YFV).

Main Results:

• CMPK2 expression restricts ZIKV replication by inhibiting viral translation.
• CMPK2 exhibits broad-spectrum antiviral activity against multiple pathogenic flaviviruses.
• The N-terminal domain (NTD) of CMPK2, independent of kinase activity, is sufficient for antiviral function.
• Seven conserved cysteine residues in the NTD are critical for CMPK2's antiviral efficacy.
• Mitochondrial localization of CMPK2 is essential for its antiviral effects.

Conclusions:

• CMPK2 is a key antiviral effector induced by IFN-I, acting by inhibiting flavivirus translation.
• The NTD of CMPK2, particularly conserved cysteine residues, mediates its broad antiviral activity.
• CMPK2 represents a promising host-targeted therapeutic candidate for pan-flavivirus infections.