Optimization of genetically encoded voltage and calcium indicators for in vivo imaging

The GENIE Project Team at HHMI Janelia Research Campus have developed a multiple genetically-encoded fluorescent indicators including the jGCaMP8 Calcium indicator family, the Voltron and Positron voltage indicators, and animal models incorporating these indicators. This poster provides updates on developments in each tool and how to obtain them. Chemigenetic voltage indicator improvement: Voltron2 showed a 65% increase in 1AP sensitivity and 3x better subthreshold membrane potential detection. Mutations in the voltage-sensing domain (Ace2N) were swapped between various types of voltage indicators and compared with patch-clamp. A new positive-going variant, Positron2, showed a 300% improvement in sensitivity. jGCaMP8s and 8m transgenic mice: TetO-jGCaMP8s mouse has ~5X increased SNR compared to TetO-GCaMP6s. Sensitivity and fast kinetics match AAV performance. TIGRE jGCaMP8s/m knock-in mice stably expressed in targeted neuronal subpopulations with reduced tetTA toxicity effects. Mice available soon from JAX.