Seitz, I. | bioRxiv Science

bioRxiv2024

Folding of mRNA-DNA origami for controlled translation and viral vector packaging

mRNA is an important molecule in vaccine development and treatment of genetic disorders. Its capability to hybridize with DNA oligonucleotides in a programmable manner facilitates the formation of RNA-DNA origami structures, which can possess a well-defined morphology and serve as rigid supports for mRNA delivery. However, to date, compre- hensive studies on the requirements for efficient folding of mRNA into distinct mRNA-DNA structures while preserving its translation func- tionality remain elusive. Here, we systematically investigate the impact of design parameters on the folding of protein-encoding mRNA into mRNA-DNA origami structures and demonstrate the importance of the availability of ribosome-binding sequences on the translation effi- ciency. Furthermore, these hybrid structures can be encapsulated inside virus capsids for protecting them against nuclease degradation and also for enhancing their cellular uptake. This multicomponent system therefore showcases a modular and versatile nanocarrier. Our work pro- vides valuable insight into the design of mRNA-DNA origami structures contributing to the development of mRNA-based gene delivery platforms.

bioengineering↗

bioRxiv2022

DNA origami directed virus capsid polymorphism

Most known viruses protect their genome by encapsulating it inside a protein capsid. Viral capsids can adopt various geometries, most iconically characterized by icosahedral or helical symmetries. The assembly process of native capsids is highly cooperative and governed by the protein geometry, protein-protein as well as protein-nucleic acid interactions. Importantly, the absolute control over the size and shape of virus capsids would have imminent advantages in the development of new vaccines and delivery systems. However, tools to direct the assembly process in a programmable manner are exceedingly elusive or strictly limited to specific structures. Here, we introduce a modular approach by demonstrating DNA origami directed polymorphism of single protein subunit capsids. We achieve control over the capsid shape, size, and topology by employing user-defined DNA origami nanostructures as binding and assembly platforms for the capsid proteins. Binding assays and single-particle cryo-electron microscopy reconstruction show that the DNA origami nanoshapes are efficiently encapsulated within the capsid. Further, we observe that helical arrangement of hexameric capsomers is the preferred mode of packing, while a negative curvature of the origami structure is not well tolerated. The capsid proteins assemble on DNA origami in single or double layer configurations depending on the applied stoichiometry. In addition, the obtained viral capsid coatings are able to efficiently shield the encapsulated DNA origami from nuclease degradation and prevent the structures from aggregation. Therefore, these findings may in addition find direct implementations in DNA nanotechnology-based bioengineering by paving the way for the next-generation cargo protection and targeting strategies.

bioengineering↗