Tonight we heard from two invited speakers, David Savage and Jeff Tabor, who are unique in that they were also instructors of previous CSH Synthetic Biology courses. The fact that past instructors have returned as speakers shows that the Synthetic Biology course is on its way towards becoming a tradition that will be sustained by a supportive community.
David Savage, from UC Berkeley, gave us an update on his biosensor engineering project, where his group designs fluorescent proteins that switch states (on vs. off) when they bind to fatty acids. Rather than synthesize variants to alter single amino acids, they have taken a cue from nature, which shuffles around large conserved protein blocks to generate new functions. The group uses transposons to insert a fluorescent protein gene into various positions within allosteric switch protein. They interrogated the large collection of variants for candidates that function as switches and found one that allows E. coli to flash green on and off, in a matter of seconds, in response to fatty acids!
Tom Knight, from Gingko Bioworks (our invited speaker for tomorrow), was also in the audience. At our courses, speakers often socialize in an environment where fresh ideas are shared amongst colleagues as well as with new synthetic biologists.
Jeff Tabor, from Rice University, presented an overview of gene network dynamics and how his lab uses clever tools to investigate gene circuits. He reminded us that the p53 two-repressor network is one natural example of the remarkable ability of a single gene network to display distinct dynamics (several quick oscillations vs. a single long burst of activity) in response to different stimuli (gamma vs. UV radiation). This phenomenon is important and intriguing, but difficult to study with stimuli that are hard to control (chemicals, temperature across a large volume, etc.). So, Jeff’s group uses light as a highly tunable stimulus; it can be added and subtracted, as well as dialed up and down, very quickly and easily.
He shared some amazing results from experiments where gene expression in engineered bacteria is controlled by light in a predictable way. First, a desired gene expression pattern (rising and falling in a specific way over time) was mapped out, and then Jeff’s group ‘asked’ a computer program to tell the researchers what pattern of light to shine onto the bacteria in order to replicate the desired pattern. The real results matched the pattern almost perfectly!
We were very excited to see the latest discoveries from our past lecturers. The group continued discussions late into the night over wine and cheese.