Endosymbiotic bacteria have evolved intricate delivery systems that enable these organisms to interface with host biology. The extracellular contractile injection systems (eCISs), are syringe-like macromolecular complexes that inject protein payloads into eukaryotic cells by driving a spike through the cellular membrane. In recent years, many synthetic biologists have paid more attention to a subtype of eCISs: the Photorhabdus virulence cassette (PVC). Because it has been shown that it can be targeted by synthetic biology methods other than the original insect cells, such as mice and human cells. ^[1]
At the same time, our team noted the increasing demand for weight-loss drugs in recent years, so we set our sights on Uncoupling protein UCP1, which has excellent potential and broad application prospects as a potential target for weight loss.
In our project, we pioneered a highly programmable protein delivery system for iGEM, PVC, and we combined UCP1's potential as a therapeutic target for weight loss with a novel protein delivery system. we first engineered Escherichia coli to produce PVCs from P. asymbiotica ATCC 43949 (PVCpnf) using a method similar to the one published by Kreitz et al. Similar to their design, we split the PVC system into separate structural/accessory plasmid (pPVC) and payload/regulatory plasmid (pPayload). pPVC and pPayload are modified in synthetic biology by using various components to obtain PVC and payload with different targets or different functions. pPVC is responsible for packaging and targeting, pPayload is responsible for playing a specified role, and finally the whole system can complete the delivery of payload. And each PVC can be matched with any payload, and finally jointly build different PVC systems to achieve different purposes.