BME PhD Prospectus Defense - Justin Letendre


BME PhD Prospectus Defense - Justin Letendre


<bTitle:<> “Advanced Synthetic Circuits for Logical Genetic Manipulation”

Committee: Wilson Wong, PhD – BME (Advisor, Chair) John Ngo, PhD – BME Doug Densmore, PhD – ECE Jerry Chen, PhD – Biology

Abstract: Synthetic biological circuits have demonstrated incredible promise for engineering complex, logical control over gene expression. Recently, the Boolean Logic and Arithmetic through DNA Excision (BLADE) single-layer circuit design has enabled the fabrication of the most complex circuits to date in mammalian cells using site-specific recombinases (SSRs). While logic circuits have proven invaluable for cell-based computation, their digital (on or off) behavior lacks the ability to finely tune levels of gene expression. Additionally, it remains difficult to engineer reliable behavior in cells due to a lack of understanding into how circuit components will perform when coupled together. To address these challenges, I seek to develop a suite of BLADE/CRISPR (BLASR) interfacing circuits, concatenating SSR-based logic computation with the dynamic expression modulation afforded by the dCas9-VPR transcriptional activator. I will demonstrate the capabilities of the BLASR system by constructing two of the most complicated circuits to date in mammalian cells: a digital-to-analog converter and genetic multiplier circuit. I will also present a workflow for relating promoter strength (input) to SSR activity (output) to allow greater predictability of logic circuits in new contexts. To demonstrate the utility of these SSR transfer functions, I will identify several complex cell phenotypes using traditionally non-specific promoters by titrating recombinase activity independent of promoter strength, thereby mitigating off-target activity and producing the intended response in the desired cell type. This body of work will provide gene circuit tools for the continued advancement of precise gene expression control.


12:00pm on Friday, November 8th 2019


44 Cummington Mall, room 203


ENG Home, BME Home