Assessing eukaryotic initiation factor 4F subunit essentiality by CRISPR-induced gene ablation in the mouse

Area of Science:

• Molecular Biology
• Genetics
• Developmental Biology

Background:

• The eukaryotic translation initiation factor 4F (eIF4F) complex is crucial for cap-dependent translation initiation.
• eIF4F is a heterotrimer comprising eIF4E (cap-binding), eIF4A (RNA helicase), and eIF4G (scaffolding protein).
• Mammalian cells express paralogs for eIF4A (eIF4A1, eIF4A2) and eIF4G (eIF4G1, eIF4G3), allowing for complex versatility.

Purpose of the Study:

• To investigate the essentiality of eIF4F subunits in mouse development and tumorigenesis.
• To determine the roles of eIF4A2 and eIF4G3 in spermatogenesis.
• To assess the impact of eIF4F subunit deficiencies on Myc-driven lymphoma development and chemotherapy response.

Main Methods:

• CRISPR/Cas9 gene editing was employed to generate mouse strains with targeted ablation of eIF4F subunit genes.
• Viability and developmental roles of individual eIF4F subunit knockouts were assessed.
• eIF4F subunit mutant mice were crossed with the Eμ-Myc lymphoma model to study tumor development and treatment response.

Main Results:

• Eif4e, Eif4g1, and Eif4a1 are essential genes for mouse viability.
• Eif4g3 and Eif4a2 are dispensable for viability but essential for spermatogenesis.
• Heterozygosity for Eif4e or Eif4a1 significantly delayed tumor onset in Eμ-Myc mice, and derived tumors showed enhanced doxorubicin sensitivity.

Conclusions:

• eIF4A2 and eIF4G3 have non-essential roles in embryonic gene expression but are vital for male fertility.
• Reducing eIF4E or eIF4A1 levels offers protection against Myc-driven lymphoma.
• Targeting eIF4E or eIF4A1 may represent a therapeutic strategy for lymphoma by delaying tumor progression and sensitizing to chemotherapy.