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Team:Michigan/Project
From 2010.igem.org
Overall project
Our project has several different tracks that we will be working on in the wet-lab simultaneously. These tracks include quorum sensing, pili hyperexpression, and surface display. We made the decision to work in several tracks in order to maximize the efficiency of our lab teams. Our goal is to be able to combine all of these parts in the end and form an organism that will be able to effectively flocculate microalgae.
Pili Hyperexpression
Type 1 pili (also known as fimbriae) are proteinaceous adhesins that are found on the surface of E. coli. One cell can contain up to 100 pili, which can form up to 2 um long. The pili help E. coli. form biofilms.
The pili are controlled by the fim operon. This operon consists of several genes. The pili themselves are composed of several thousand subunits of FimA. The tip of each pili consists of the genes FimF, FimG, and FimH. FimH is an adhesin and is linked to FimA through FimF and FimG. Inside the cell, FimC carries proteins to the structural platform, FimD, which then assembles the pilus rod. You can see this visually in Fig. 1 [1]. This whole process is regulated by the recombinases FimB and FimE. These genes control an invertible DNA sequence, which, when in the "on" position, promotes the production of pili. You can learn more about the regulatory system in the modeling section.
By overproducing the pili, we hope to increase flocculation. By hyperexpressing FimH, we can increase the amount of pilus adhesin (Fig. 2), which will hopefully strengthen the E. coli binding to the algae. You can find the pili team's lab notebook here.
Quorum Sensing
Our cells will use quorum sensing to determine when the flocculation will start. The cells will produce an inducer either AHL or AI-2. You can find their lab notebook here.
Virus Surface Display
Oil Sands
References
1. Vetsch, M., Puorger, C., Pilus chaperones represent a new type of protein-folding catalyst. Nature 431, 329-332 (2004).
