Fig. 4: Reprogramming PVCs to achieve targeted delivery in mice.
From: Programmable protein delivery with a bacterial contractile injection system
a, AlphaFold-predicted structures of novel mouse-targeting Pvc13 (tail fibre) designs. We replaced the wild-type binding ___domain of Pvc13 with an expanded tropism variant of the Ad5 binding ___domain (Ad5-knob(RGD/PK7)) or a nanobody (Nb) targeting mouse MHC class II protein (MHCII). b, Novel mouse-targeting PVC designs exhibit enhanced activity across mouse cell lines and primary cells. PVCs deficient for the spike tip protein (Pvc10) were used as negative controls for both novel Pvc13 designs. c, Left, schematic showing protein delivery in the mouse brain with PVCs. Right, PVCs equipped with Pvc13–Ad5-knob(RGD/PK7) produce tdTomato signal in the hippocampus of Ai9 (loxP-tdTomato) mice. Fluorescence was abolished when the spike tip protein (Pvc10) was deleted, confirming that the observed activity was mediated by the PVC. Injection sites are shown with white arrows. Scale bars, 500 μm. d, PVCs target neurons in vivo. Intracranial injections were performed as in c and single-cell extracts from treated brains were analysed with flow cytometry. The flow cytometry gating scheme is shown in Extended Data Fig. 8a. MFI, mean fluorescence intensity. e, Intracranial PVC injections do not induce immune cell migration to the CNS. The flow cytometry gating scheme is shown in Extended Data Fig. 8d. f, PVCs are transient in the mouse brain. Intact particles can be readily purified from treated mouse brains after 0 or 1 day, but not after 7 days, indicating that PVCs do not persist in brain tissues for extended periods. Scale bar, 500 nm. Data are mean (b) or mean ± s.d. (d,e) with n = 2 (b) or n = 3 (d,e) biological replicates; two-way ANOVA with Bonferroni post hoc test (d,e).
