Recombinant Drosophila virilis Eukaryotic translation initiation factor 3 subunit C (eIF3-S8), partial

Overview of eIF3-S8 in Drosophila virilis

Eukaryotic translation initiation factor 3 subunit C (eIF3-S8), encoded by the eIF3c gene, is a critical component of the multi-protein eIF3 complex. This complex coordinates ribosome assembly and mRNA recruitment during translation initiation. In Drosophila virilis, eIF3-S8 is part of the conserved eIF3 machinery but has species-specific structural and functional nuances compared to homologs in Drosophila melanogaster and other eukaryotes . Recombinant eIF3-S8 refers to a truncated version of the protein produced in vitro for biochemical and functional studies.

Functional Role in Translation Initiation

eIF3-S8 contributes to:

• Ribosomal subunit dissociation: Prevents premature 60S subunit binding to 40S during pre-initiation complex (PIC) formation .

• mRNA recruitment: Binds mRNA structural elements (e.g., stem-loops) via its RNA-binding motifs to enhance translation efficiency .

• Coordination with other eIFs: Forms a scaffold with eIF3a, eIF3b, and eIF3i to stabilize the PIC .

Key Functional Studies:

Recombinant Production and Characterization

Recombinant Drosophila virilis eIF3-S8 is typically expressed in E. coli or insect cell systems. Example parameters from homologs:

• Expression system: E. coli (e.g., BL21 strains) for cost-effective production .

• Tagging: His-tag or GST-tag for purification .

• Purity: >85% via SDS-PAGE .

Storage and Stability:

• Store at -20°C or -80°C in glycerol-containing buffers .

• Avoid repeated freeze-thaw cycles .

Applications in Research

• Mechanistic studies: Elucidate eIF3’s role in non-canonical translation (e.g., viral IRES elements) .

• Drug discovery: Screen for translation inhibitors targeting eIF3-S8’s RNA-binding sites .

• Structural biology: Cryo-EM studies of eIF3–ribosome complexes .

Limitations and Research Gaps

• Partial sequence coverage: Current recombinant constructs lack full-length protein, limiting functional assays .

• Species-specific data: Most structural insights derive from D. melanogaster or human eIF3c, necessitating validation in D. virilis .

References to Key Studies

1. Structural analysis of eIF3–40S interactions .

2. Role of eIF3c in mRNA recruitment .

3. Recombinant production protocols for insect cell systems .