Fig. 3: After each division, nuclear speed covaries with local nuclear density, and nuclei move into nearby open space. | Nature Communications

Fig. 3: After each division, nuclear speed covaries with local nuclear density, and nuclei move into nearby open space.

From: Nuclear speed and cycle length co-vary with local density during syncytial blastoderm formation in a cricket

Fig. 3

a Nuclear positions along the anterior-posterior axis (\(x\)) over 200 minutes of syncytial development (\(y\)). Each dot represents a nucleus-timepoint, colored by its speed. The first zygotic division occurred ~60% from the anterior pole. Imaging began after the second division. b Schematic of nuclei, partitioned into anterior, middle, and posterior thirds (turquoise, dark blue, and purple, respectively). c Speed oscillations dissipate earliest in the middle third, where local nuclear density is highest. Center line represents median, shaded regions represent 25th−75th percentiles. df Nuclei from all time points and positions were grouped into bins, according to local density (number of nuclei within a 150-µm radius; “low”: \( < \) 11 nuclei, “medium”: \(\ge\) 11 and \( < \) 29 nuclei, “high”: \(\ge\) 29 nuclei). d Nuclear speed traces after each mitosis concluded. Nuclei move relatively quickly after a division and then slow down. We refer to these periods as “Phase A” and “Phase B”. Center line represents median, shaded regions represent 25th−75th percentiles. e, f Nuclear speed versus local density. Data are shown from two periods post-division: t = 3 to t = 13.5 min (e) and t = 33 min to t = 39 min (f). Black line is the best-fit curve of the form \(y={y}_{0}{e}^{-x/{x}_{0}}\), yielding a density scale (\({x}_{0}\)) of 30.4 density units for Phase A (90% CI: 28.8-32.1) and 120.4 density units for Phase B (90% CI: 73.4-167.4). g We calculated a nucleus’s tendency to move into nearby open space as its movement vector’s correlation with the vector from its current position to the centroid of its Voronoi cell (pink star). Nuclei were also subdivided into those in the “interior” of the embryo, or in the periplasm (defined here as within 75 µm of the eggshell. The distribution of single time-step nuclear movements (n) is shown for each bin. Phase A nuclei in the interior tend to move into nearby open space, but not when they are in the periplasm (left). Phase B nuclei tend not to do so regardless of where they are (right). White line represents median, boxes represent 25th−75th percentiles, whiskers show range. Source data are provided as a Source Data file.

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