Figure 1.

The centrosome of Dictyostelium cells migrating in microchannels or micropillar arrays along a cAMP gradient is preferentially located behind the nucleus. (a) Scheme (left) and representative microscopy images (right) of an aggregation competent Dictyostelium cell migrating in a microchannel along a gradient of cAMP. The cells express both the nuclear marker mRFP-histone (red), and GFP-tubulin (green) to highlight centrosomes and microtubules. Time is indicated in min and s at the top. The cell shape is highlighted by a yellow dashed line. (b) Principle of quantification. (c) Centrosome position during migration in microchannels within a gradient of cAMP. N = 3, number of cells = 32. (d) Representative images of Dictyostelium cells showing analysis of nucleus (red) and centrosome (green) centroid distances (indicated by “X”) (left). Histogram (right) displays the quantification of the distances between the nucleus and centrosome centroids during migration in microchannels and micropillar arrays along a cAMP gradient. N = 3, number of cells = 30. (e) Scheme (left), and representative microscopy images (right) of a cell migrating in a field of micropillars along a gradient of cAMP gradient, recorded with a time interval of 10 s per frame. The white arrows indicate the trajectory of the cell. The numbers indicate the time in min and s. (f) Quantification of the centrosome position during migration in an micropillar array along a gradient of cAMP. N = 3, number of cells = 30. Scale bars are 10 µm. * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001 are significant, and ns = not significant.