Poster abstracts
Poster number 57 submitted by Rohan Krishna
eIF4B and eIF4H direct specialized translation of distinct antiviral translation programs
Rohan Krishna (Department of Biochemistry, Case Western Reserve University), Joseph Luna (Department of Biochemistry, Case Western Reserve University)
Abstract:
Interferon stimulated genes (ISGs) are rapidly translated during the innate immune response to inhibit RNA viral replication. RNA helicase eIF4A, plays a critical role in mediating ISG translation by unwinding complex secondary structures in mRNAs. RNA binding proteins, eIF4B and eIF4H, are primary cofactors of eIF4A that are thought to serve redundant functions in promoting the helicase activity of eIF4A. Here we present evidence that eIF4B and eIF4H play different roles by binding mutually exclusively to eIF4A, creating two flavors of translation initiation complexes with unique ISG mRNA preferences. Using CRISPR knockout cells, we observe that eIF4B, not eIF4H is required for efficient translation of ISGs to suppress Hepatitis C Virus replication. We used CLIP-Seq to demonstrate that eIF4A exhibits distinct mRNA binding patterns when associated with eIF4B versus eIF4H, revealing cofactor dependent specificity in ISG mRNA selection during the interferon response. This suggests that by modulating eIF4B and eIF4H availability, cells can selectively control translation of distinct subsets of ISGs. Our current work aims to define ISG-specific translational programs regulated by eIF4B/4H through a combination of ribosome profiling and CLIP-seq in knockout cell lines. Using these hits, we will identify if the translation of specific mRNA transcripts is due to differences in ISG transcript sequence/structure or due to protein features in eIF4B and eIF4H. These results will establish a new paradigm for eIF4A functionality during innate immunity and reveal fundamental principles governing specialized translation in immune responses.
Keywords: translation , virus, interferon