Fig. 1: Customization and simplification of SFV-based programmable VLP system.

a Composition and transgene delivery mechanisms of mRNA VLPs based on two distinct RNA viruses: lentivirus (LV-based mRNA VLPs, left) and SFV (SFV-based mRNA VLPs, right). SFV-based mRNA VLPs are streamlined, requiring only viral capsid (CA) and envelope proteins for the packaging and translation of mRNA. In contrast, LV-based mRNA VLPs necessitate additional viral proteins such as reverse transcriptase (RT), protease (PR), integrase (IN), nucleocapsid (NC), and matrix (MA), in addition to capsid and envelope proteins. Notably, some lentivirus-based mRNA VLPs require reverse transcription of RNA into cDNA and subsequent nuclear import for transgene expression (process ①), while others (process ②), like SFV-based VLPs, facilitate direct translation. b Construction and simplification of the VLP vector. The initial packaging included non-structural protein (NSP) as one of the helpers, a component eliminated in the final simplified packaging system. c Packaging and delivery efficiency with different packaging systems. The luciferase mRNA was packaged using different packaging systems. Packaging efficiency was assessed by the number of VLP genomic copies per cell, whilst delivery efficiency is measured by measuring the luminescence intensity of the produced luciferase. VLP genomic copies (n = 3) and luminescence (n = 9) in delivered BHK-21 cells were assessed. The left y-axis illustrated packaging efficiency, represented by the quantity of produced VLP per cell. The right y-axis depicted in vitro delivery efficiency, measured by luminescence intensity in the delivered cells. Error bars represented the mean with standard deviation (SD) of independent replicates. Statistical analysis details were provided in the Supplementary Data 1. Source data are provided as a Source Data file.