Precise optical control of gene expression in C. elegans

Researchers have developed and used an improved genetic code expansion system for optical control of gene expression in an animal.

Researchers in the lab of Dr Sebastian Greiss, Synthsys PI and member of the Centre for Discovery Brain Sciences, used a laser to activate expression of a gene in targeted C. elegans neurons. This system was then used to study a neural circuit at single cell resolution.

This approach is named Laser Targeted Activation of Cre-Lox recombination (LaserTAC). LaserTAC is fast and within the technical capabilities of any lab currently able to perform laser ablation.

They demonstrate the utility of LaserTAC by using it to target the expression of optogenetic channels to individual C. elegans touch sensory neurons within a left/right pair (PLML and PLMR). These individual neurons cannot be targeted by other methods, and their approach allows us to study their contribution to behaviour for the first time. Distinct and synergistic roles were revealed for these neurons.

This work, published in eLife and in collaboration with researchers in the Medical Research Council Laboratory of Molecular Biology, Cambridge, demonstrates how genetic code expansion and optical targeting can be combined to break the symmetry of neuron pairs and dissect behavioural outputs of individual neurons that cannot be genetically targeted.