Synthetic Gene Circuits Reveal how KRAS(G12V) Affects Cell Proliferation & Migration Patterns

Small chemicals and light can serve as stimuli for controlling synthetic gene circuits to probe biological networks relevant to systems biology and biological physics. We previously developed Light-Inducible Tuner (LITer) gene circuits that have a wide dynamic range of gene expression, low gene expression noise, and an ability to respond with gene expression changes to both chemicals and light. As a foundation for exploring gene regulatory networks, we have created LITer variants controlling half-a-dozen functional genes. Here we present results from perturbing the levels of proto-oncogene KRAS(G12V). We explore a range of cellular features including cellular distance travelled, velocity, acceleration, proliferation, and invasion versus KRAS(G12V) levels. This study reveals that functional genes can have nontrivial effects at intermediate levels of activity, illustrating the utility of analog synthetic gene circuits to complement existing knock-out and overexpression genetic approaches. Furthermore, these tools may reveal quantitatively biological thresholds for functional genes to produce cellular phenotypes.