Xenbase Image ID: 176000

Figure 4. A Cell-Size Threshold, Not Spatial Position, Dictates ZGA Onset. (A and E) Schematic of confocal imaging of the vegetal pole (VP) (A) and animal pole (AP) (E) in embryos at ∼C13. Z-position along the AV axis in the indicated directions. (B, C, F, and G) Heatmap contour plot of nuclear EU-RNA amount as a function of Z-position and distance from embryo center within the vegetal pole (B) and animal pole (F), and of Z-position and cell size within the vegetal pole (C) and animal pole (G). Color scales indicate low (blue) to high (red) transcription. (D and H) EU-RNA amount and percent of transcriptionally active cells as a function of Z-position within the indicated sub-regions of the vegetal pole (D) and animal pole (H). Data in top panel of (D) are represented as mean ± standard deviation. Data fit for visual aid in (H). (I) Predicted decision boundaries for ZGA with a perfect sizer (top left), positional bias (top right), and mixed sizer and positional effect (bottom). Gray, inactive; red, active; green line, decision boundary for ZGA. (J) Logistic regression boundary decision for ZGA as a function of cell size and Z-position along the AV axis. Each point is a bin of 25 μm by Z-position followed by a bin of 250 cells for each of 8 embryos at ∼C12.8–C13.5. Binary activation based on threshold amount EU-RNA. Black square, inactive cells; red square, active cells; green line, decision boundary of ZGA. See also Figure S4. 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

Return to previous page