Team:Berkeley/Project/Vesicle Buster

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Overview

The Vesicle Buster is designed to degrade the vesicle membrane after lysis by degrading the phospholipids and creating pores in the membrane. It allows the payload that has been released into the vesicle by Self-lysis to move to the cytoplasm of the Choanoflagellate.

Construct

Vesicle buster construct.png

  • Pcon: constitutive promoter
  • Perfrinogen O (PFO): a protein from Clostridium perfringens that oligomerizes to form pores in cholesterol-containing membranes
  • Phospholipase C (PLC): a phospholipase from Clostridium perfringens that degrades eukaryotic phospholipids
  • Degradation tags (ssDeg): Eukaryotic degradation tag
  • Pre-pros: a sequence that targets proteins to the periplasm of E. coli



From Mammalian to Lower Metazoan Delivery


Payload Delivery Device


Vesicle Buster We derived the vesicle buster device from a construct built in the Anderson Lab and intended to be used in a mammalian system. There were several design challenges the vesicle buster had to satisfy in order to properly function in our delivery scheme. Because of the short time window between ingestion and digestion, the vesicle buster had to be constitutively expressed and ready to act upon self lysis. Stable expression of the vesicle buster was accomplished by placing it under the control of Pcon, a constitutive promoter. Since the bacteria stably express the vesicle buster, the device also cannot harm the bacteria and must act only on the choanoflagellate’s membrane. This specificity was satisfied by using PFO and PLC. PFO acts only on a cholesterol-based membrane and does not affect E. coli’s cell wall. PLC also targets phsopholipids found only in eukaryotic membranes. Finally, once the food vesicle is opened and its contents are released into the cytoplasm, PLC and PFO must be prevented from breaking down any other membrane and creating further damage to the choanoflagellate. For this reason, degradation tags were added to these enzymes.