Module 2 - Encapsulsation Overview

Encapsulation Rationale

In nature, encapsulation pathways such as spore formation, aliginate biosynthesis and colanic acid production all share one common feature: they require a large number of genes. For this reason, we decided that the best way encapsulate our chassis was via the modulation of an existing pathway.

E.coli naturally produces a harmless acid resistant polymer known as colanic acid. Colanic acid is a polymer of glucose, galactose and glucuronic acid. By tapping into the pathway that initiates colanic acid biosynthesis, we can turn on its production via the modulation of a gene called RcsB.

In nature, colanic acid acts as a binding agent between individual cells over which a biofilm can be formed. While colanic acid itself is harmless, biofilm formation is associated with the production of a number of virulence factors. To prevent biofilm formation from occuring, we have tapped into a second pathway such that our cells become locked into colanic acid production. The gene responsible for preventing biofilm formation is a transcription factor called YgiV.

In nature, colanic acid is associated with but not attached to the cell surface. To facilitate whole cell encapsulation, we have modified a third pathway to fix the colanic acid to the surface of the cell. This involves an enzyme called Rfal.

  About RcsB, YgiV and Rfal.