Poxvirus Portal Complex Structure Revealed by Cryo-ET

Researchers have elucidated the in situ structure of the poxvirus portal complex, a conserved hexameric assembly that traverses the core wall of the vaccinia virus. This breakthrough, published online in Nature on July 29, 2026, utilized cryo-electron tomography (cryo-ET) to provide unprecedented detail on this critical viral component. The study, identified by the DOI 10.1038/s41586-026-10856-2, reveals how the portal complex is intrinsically linked to several key viral functions essential for its lifecycle. Specifically, the research demonstrates the complex's involvement in viral assembly, the process by which new virus particles are constructed within the host cell. Furthermore, the study illustrates the portal complex's role in the release of messenger RNA (mRNA) from the virion, a step crucial for initiating viral gene expression upon infection. The research also details the complex's association with genome uncoating, the process by which the viral DNA is released from the capsid into the host cell's cytoplasm, making it accessible for replication. The poxvirus portal complex is a dodecameric ring structure, composed of twelve identical protein subunits, which acts as a channel or conduit through the viral envelope and capsid. Its conserved nature across various poxviruses suggests a fundamental importance in their biology. Vaccinia virus, a well-studied member of the Poxviridae family, is known for its large, complex, double-stranded DNA genome and its ability to replicate in the cytoplasm of host cells. The discovery of the portal complex's structure and its functional associations sheds light on the intricate mechanisms employed by these viruses to manage their genetic material and orchestrate their replication. Understanding these molecular details is vital for developing antiviral strategies, as targeting such essential viral machinery could lead to the inhibition of viral propagation. The application of cryo-ET has been instrumental in visualizing macromolecular structures in their native cellular environments, overcoming limitations of traditional electron microscopy techniques. This advanced imaging method allows for the reconstruction of three-dimensional structures at near-atomic resolution, providing insights into the dynamic interactions of viral components. The findings from this study contribute significantly to the broader field of virology, offering a deeper comprehension of viral assembly, entry, and genome management. Future research may build upon these structural insights to design novel therapeutics that specifically disrupt the function of the poxvirus portal complex, thereby combating poxvirus infections.