Xenbase Image ID: 175997

Figure 1. Spatiotemporal Patterning of Zygotic Genome Activation at the Single-Cell Level in Xenopus Early Embryogenesis. A) Hypotheses for patterning of genome activation in blastula embryos based on a timer and sizer model, respectively. Color scale indicates low (gray) to high (red) transcription. (B) Schematic of metabolic labeling of nascent zygotic transcripts in early Xenopus embryos. (C) Confocal images of nascent EU-RNA (upper panel) and heatmap of its intensity (lower panel) in individual nucleus for blastula-stage embryos from embryonic cleavage 10 (C10) to 14 (C14). Color scale indicates original EU-RNA intensity from low (blue) to high (red), without background subtraction. AP, animal pole; VP, vegetal pole. Dashed line demarcates individual embryos. Scale bar, 100 μm. (D) 3D reconstruction and heatmap of nascent EU-RNA amount with background subtraction in individual nucleus of blastula embryos. Color scale indicates low (blue) to high (red) transcription. No significant EU-RNA signal until C12. (E–G) Ensemble view (E), single-cell view (F), and regional view (G) of ZGA. Each point indicates one embryo. Exponential (E) or sigmoidal (F and G) fit to data as visual aid. (E) Ensemble view of ZGA: total nascent EU-RNA amount with background subtraction within entire blastula embryos. (F) Single-cell view of ZGA: percentage of cells above the threshold EU-RNA amount in nucleus of each blastula embryo. (G) Regional view of ZGA: percentage of cells above the threshold EU-RNA amount in nucleus of the animal (A, red) and vegetal (V, blue) pole in each blastula embryo. Animal pole and vegetal pole at 200-μm depth from the top and the bottom, respectively. See also Figure S1. Image published in: Chen H et al. (2019) Copyright © 2019. Image reproduced with permission of the Publisher, Elsevier B. V. Larger Image Printer Friendly View

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