Data from: HP1a dynamics in the early drosophila embryo

Flies homozygous for the expression of ectopic GFP-HP1a on the second chromosome (+, GFP-HP1a/CyO; +) were allowed to lay embryos on apple juice plates supplemented with yeast paste at 25°C. Embryos were collected by hand and dechorionated in 50% bleach before being mounted for live imaging. Embryos were imaged using a Zeiss 880 Airyscan microscope with a 63x/1.4 oil immersion objective. Time-lapse image stacks were collected every 30 seconds with a Z-spacing of 0.36μm. Imaging at least part of nuclear cycle 13 (NC 13) allowed the start of NC14 (time=0 sec) to be clearly defined as the first time point where circular nuclei appear following mitosis. All movies were Airyscan-processed using Zen 2.3 software and the first 72 time points of NC 14 (max36 minutes) were analyzed using Arivis software. Briefly, HP1a foci were segmented from the overall nuclear signal using an intensity threshold > 75% of the fluorescence intensity and a lower size threshold of 0.03 μm3 corresponding to approximately 10 voxels (0.085 μm x 0.085 μm x 0.36 μm). All HP1a segments found to be percolating in 3-dimensional space were merged into a single segment, and population statistics were calculated for each time point. The imaging data made accessible here are the 4-D zeiss confocal modies converted to .tif stacks in FIJI but unanalyzed and unaltered in any other way.