Sponging of cellular proteins by viral RNAs

• Abundant viral RNAs can act as sponges for cellular factors.
• Dengue and Sindbis viral RNAs sequester select cellular RNA binding proteins.
• RNA-mediated sequestration of host proteins dysregulates gene expression.
• Protein sponging has significant implications for viral pathogenesis.

Viral RNAs accumulate to high levels during infection and interact with a variety of cellular factors including miRNAs and RNA-binding proteins. Although many of these interactions exist to directly modulate replication, translation and decay of viral transcripts, evidence is emerging that abundant viral RNAs may in certain cases serve as a sponge to sequester host non-coding RNAs and proteins. By effectively reducing the ability of cellular RNA binding proteins to regulate host cell gene expression, viral RNAs can alter the response to infection and favor viral replication. This review focuses on the potential contribution that sequestration of cellular proteins by viral RNAs makes to viral replication and cytopathology.