FIGURE 2

FIGURE 2

Imaging of germplasm across scales (A–F), Imaging of individual germ granules (RNP complexes). (A,B), Stills from a 4d movie showing germplasm aggregation at the first cleavage furrow imaged on a 3i LLSM at two time points 50 seconds apart. The inset in the top right corner of the earlier time point (A) is a schematic illustrating the area that has been imaged in an animal pole view first cleavage embryo, highlighted by a blue box. One specific germ granule is framed in an orange box at the later time point (B). (C–F), This germ granule (at 31 s) was used for volume measurement by threshold segmentation in 3d. (C,D), The granule is shown in two orthogonal views. (E,F), The segmented granule in the same views, together with the measured volume. (G–I), Imaging of individual PGCs. (G) Still from a 4d movie of germplasm segregation during cell division of a PGC at the oblong stage, imaged on a spinning disk confocal microscope. Germplasm is labeled by Buc-EGFP (green), membranes by Farnesyl-mCherry (magenta) and chromatin by H2Afv-tagBFP (blue). The middle and right panels show zoom-ins of the area highlighted by a dashed white box in (G) at the timepoints in (H) and (I). (J,K) In toto imaging of germplasm in a zebrafish embryo over a 5.5 h duration on a 3i diSPIM microscope in SPIM mode. The first frame (8-cell, left) and the last frame (gastrula, right) are shown. Four large germplasm masses are observed at the 8-cell stage (J) and are partitioned into many PGCs in the gastrula (K). Germplasm is labeled by Buc-EGFP (green), membranes and actin cortex by Farnesyl-mCherry and Utrn-mCherry (magenta), respectively, and chromatin by H2Afv-tagBFP (blue).