Fig. 1. An electric field of 300mV/mm directs CHO cell migration and Golgi polarization. (A-C) Time-lapse images showing morphological polarization and directional migration of CHO cells in a DC EF. (D) Outlines of the labelled cells from A-C highlight morphological polarization and cell migration. (E-F) Golgi (red) polarization and actin (green) distribution in CHO cells cultured in the absence (E) or presence (F) of an EF for 3 hours. The cells were fixed and triple-labelled with GM130 antibody (Golgi marker, red), FITC-phalloidin (F-actin, green) and DAPI (blue). (F') Golgi polarization in control experiments with cross-current medium flow where chemical gradients, ionic gradients and fluctuation in temperature and pH were eliminated. (G) Cells with the Golgi falling in the indicated quadrant were scored. (H) An EF of 300 mV/mm increased the percentage of cells with the Golgi polarizing towards the cathode with time. Results shown are the mean±s.e.m. For each time point, a minimum of 300 cells was scored from three independent experiments. Bar, 10 µm. See also supplementary material video 1.