Baculoviruses are viruses that specifically infect insect cells and play a key role in regulating their populations. They are used both as biological control agents in agronomy and, most importantly, as expression systems for the production of recombinant proteins in structural biology (insect cell culture). Morphologically, Baculoviruses possess a nucleocapsid, the protein assembly that protects and packages the viral DNA, surrounded by a lipid envelope into which viral glycoproteins are inserted. Despite their widespread use, detailed structural studies of Baculovirus nucleocapsids remained limited at the beginning of this project.
The nucleocapsid, elongated in shape (on average 50 nm in diameter and 300 nm in length), displays two distinct ends : the “apical” cap, through which viral DNA transits, and the “basal” structure, connected to one another by the capsid. Thanks to cryo-electron microscopy, the complete structure of the AcMNPV Baculovirus nucleocapsid was resolved for the first time at high resolution by IBS researchers (Methods and Electron Microscopy group) in collaboration with the EMBL Grenoble and the ESRF.
This breakthrough provides deeper insights into the functioning of Baculoviruses, enriches the structural database of the virus, and paves the way for a more rational development of biotechnology tools based on these viruses.
Structure of AcMNPV nucleocapsid reveals DNA portal organization and packaging apparatus of circular dsDNA baculovirus. Effantin G, Kandiah E, Pelosse M. Nature Communications 2025 ; 16(1):4844. https://doi.org/10.1038/s41467-025-60152-2
Contact : Gregory Effantin (IBS/Methods and Electron Microscopy Group)