Changes in nuclear shape occur rapidly in migrating border cell clusters. (A) Plots of the average ± SEM of each indicated parameter relative to the time of delamination. n = 10 movies. (B) Nuclear aspect ratio of each leading cell’s nucleus aligned to the protrusion axis, n = 10. (C) Representative plot showing an example where nuclear width and protrusion width simultaneously oscillate while the protrusion tip width changes variably. (D) Individual (dots) and average ± SEM correlation between nuclear width and protrusion base width or between protrusion tip and base width for the first border cell protrusion of each movie. A two-sided, unpaired t test yields P = 0.02. (E) Average difference between the protrusion base and protrusion tip. (E and F)n = 10 leading cells. (F) Images from a time-lapse series with the leading cell nucleus marked with GFP.NLS. Images were acquired every 20 s. Bottom right: projection of time points. (G) ZY view of border cell cluster leading cell and following cell over time to show the expansion and shrinking of the juncture as the cluster moves through it. (H–J) Example images of nuclei from time-lapse series of control leader, follower, or RacN17 dominant negative expressing border cells. Right: projection of time points. (K) Plot of the average change in nuclear aspect ratio; bars: mean ± SEM; dots: value for one nucleus; n = 51 (control), n = 29 (RacN17). A Mann–Whitney test was used to test for statistical significance. Scale bars: 10 µm. Genotypes and experimental replicates reported in Table S2.