Giant DNA viruses encode a hallmark translation initiation complex of eukaryotic life
Summary
bioRxiv. 2025 Sep 30:2025.09.30.678621. doi: 10.1101/2025.09.30.678621. In contrast to living organisms, viruses were long thought to lack protein synthesis machinery and instead depend on host factors to translate viral transcripts. Here, we discover that giant DNA viruses encode a distinct and functional IF4F translation-initiation complex to drive protein synthesis, thereby blurring the line between cellular and acellular biology. During infection, eukaryotic IF4F on host ribosomes is re
Content
# Giant DNA viruses encode a hallmark translation initiation complex of eukaryotic life
*Published: 2026 Mar 5*
bioRxiv. 2025 Sep 30:2025.09.30.678621. doi: 10.1101/2025.09.30.678621.
In contrast to living organisms, viruses were long thought to lack protein
synthesis machinery and instead depend on host factors to translate viral
transcripts. Here, we discover that giant DNA viruses encode a distinct and
functional IF4F translation-initiation complex to drive protein synthesis,
thereby blurring the line between cellular and acellular biology. During
infection, eukaryotic IF4F on host ribosomes is replaced by an essential viral
IF4F that regulates viral translation, virion formation, and replication
plasticity during altered host states. Structural dissection of viral IF4F
reveals that the mRNA cap-binding subunit mediates exclusive interactions with
viral mRNAs, constituting a molecular switch from translating host to viral
proteins. Thus, our study establishes that viruses express a eukaryotic
translation-initiation complex for protein synthesis, illuminating a series of
evolutionary innovations in a core process of life.
DOI: 10.1016/j.cell.2026.01.008