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 sensing devices. 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 toxic to E. coli. We built a stress-regulated transcription system that drives relatively high expression of toxic proteins. This allowed us to further 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 plan more experiments to engineer a dose-dependent transcriptional response to estrogen. By fusing existing or engineered ligand dependent homodimers to ToxR, this modular system can be used to build 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 and developed a system of organizational management to synchronize our efforts for the task at hand. We created protocols and taught them to each other, using google docs to keep up with the status of sub-projects, logistics, or final steps required to complete a project. Through months of hard work, we have fine-tuned 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 with very different skill sets. Some of us have a 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.