Team:Berkeley

Biosensors have widespread applications ranging from diagnostics to environmental monitoring. Vibrio cholerae's ToxR system can be used as a component in biological devices capable of detecting a wide variety of molecules. A periplasmic domain causes ToxR homodimerization, activating transcription of the ctx promoter. By replacing the periplasmic domain of ToxR with existing or engineered ligand-dependent homodimers, we hope to link ToxR dimerization (and gene expression) to the presence of specific ligands. Initially, ToxR constructs proved to be toxic to E. coli. To address ToxR toxicity, we screened microarray data for promoters that exhibited stress-based down regulation. We constructed a negative feedback system with the rffGH promoter, which permits the use of potentially toxic proteins like our various ToxR chimeras. By fusing existing or engineered ligand dependent homodimers to ToxR, this modular system can be applied to develop new biosensors.

A protein with great potential as a general biosensor system.

Our method for expressing interesting (but toxic) proteins.

Chimeric proteins that drive translation off of the Pctx promoter.

Bacteria designed to detect environmental estrogen contamination.

We are Team Berkeley, a cohesive unit of 7 undergraduates and 3 advisers. Earlier this year, planned a complex project that was risky given the short amount of time iGEM made available. We quickly learned each others strengths and weaknesses in order to develop a system of organizational communication to synchronize our efforts for the task at hand. We created protocols and taught them to each other, and extensively used google docs to always keep up with what others were doing or what steps we have to take to complete the project. Through months of hard work, we have been able to fine tune our ability to work together. As a team, we have learned firsthand how the synthetic biology community relies on the goal-oriented cooperation of skilled individuals from very different backgrounds and skill sets. Some of us have a very strong engineering background and are very good at working with new technology while others of us have a strong biology background and work better with research problem solving. We are proud of the project that we have created which we will present at the Jamboree together in October.