Extended Data Fig. 7: Additional characterizations of designs and negative controls.

a, An example of I-V curve plot demonstrating the data processing method. The black curve represented the raw data obtained from a − 100 mV to +100 mV ramp protocol in 10 mM [Ca²⁺] solution. The gray curve represented the raw data obtained using the same ramp protocol in 0.02 mM [Ca²⁺] solution, and was defined as the background. The blue curve was obtained by subtracting the gray curve from the black curve, and was defined as the Ca²⁺ conductance. The same process was used to determine conductances for other ions as well. b, Expression of designs in Hi5 cells examined by western blot using an anti-His antibody. The four samples loaded on the gel (lanes indicated by the black bars) were whole-cell lysates of cells expressing CalC6_3 and CalC4_24, cells infected with the control virus (made from an empty pFastBac_Dual vector), and uninfected cells alone. c, The time course of currents at −100 mV in 10 mM [Ca²⁺] and 40 mM [Na⁺] extracellular solutions recorded on cells infected with the control virus. d, I-V relations obtained from a − 100 mV to +100 mV ramp protocol in 10 mM [Ca²⁺] (cyan) and 40 mM [Na⁺] (red) solutions, averaged over three separate cells infected with the control virus. The shaded regions represent bootstrapped 95% confidence intervals. e-h, Comparison of Ca²⁺ current densities elicited by the voltage step protocol in the 10 mM [Ca²⁺] extracellular solution between the designs and the negative control (without subtraction of background leak currents). e, The schematic illustration of the voltage step protocol (also shown in Fig. 3). f and g, Current densities obtained from the cells expressing CalC4_24 (f) and CalC6_3 (g). The source data are the same as those shown in Fig. 3e and f. Here, the currents are normalized by cell capacitances to obtain current densities. h, Current densities obtained from the cell treated with the control virus.