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 constructed a stress-based negative feedback transcription system. This allowed us to express relatively high levels of toxic proteins so that we could begin to engineer ToxR chimeras. We fused an estrogen-dependent dimer with ToxR hoping to create an estrogen biosensor. We observed a range of constitutive phenotypes and have more experiments planned to engineer a dose-dependent transcriptional response to estrogen. By fusing existing or engineered ligand dependent homodimers to ToxR, this modular system can be applied to develop new biosensors.

We are Team Berkeley, a cohesive unit of 7 undergraduates and 3 advisers. Earlier this year we 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.