XB-IMG-176007
Xenbase Image ID: 176007
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Figure S3. Correlation Between Nascent Zygotic Transcription and Nucleocytoplasmic (N:C) Volume Ratio. Related to Figure 3.
(A) Model for nucleocytoplasmic (N:C) volume ratio regulation of ZGA. During early embryogenesis, cell size reduction directly regulates N:C volume ratio. Cell size also regulates nucleus size by intracellular scaling, which further regulates
N:C volume ratio. In addition, the N:C volume ratio is affected by the time of cell spent in interphase.
(B) EU-RNA accumulation within individual nucleus as a function of N:C volume ratio. Data were binned in 0.05 increments of N:C ratio from 5 embryos at 8000-cell stage (log2 cell no. = 13) and represented as mean ± standard deviation.
(C) The same as (B) except that y axis represents fraction of active cells.
(D) Influence of duration in interphase on DNA replication, new zygotic transcription and N:C volume ratio. From early to late interphase, DNA replicates, transcripts accumulate, and nucleus grows. Increased nucleus size elevates N:C volume ratio.
(E) Histogram of DNA amount in cells at interphase. Integrated DNA intensity within the nucleus, background subtracted.
Data from cells smaller than the sizer threshold: cells 25-35 µm diameter in the animal pole of ~ 8000-cell stage embry- os. Bimodal peak fitting to distribution shows DNA amount from 2N (orange) to 4N (red). DNA amount correlates with
the during of a cell in interphase. A.U., arbitrary units. (F) New transcription (EU-RNA amount) as a function of duration in interphase (DNA amount) for cells smaller than the sizer threshold: cells 25-35 µm diameter. The red dots indicate the peaks 2N to 4N in subfigure (E). A.U., arbitrary units.
(G) Mean values for EU-RNA for 2N and 4N DNA bins from (F). Shows amount of new transcription (top) and percentage
of transcriptionally active cells (bottom) at early and late interphase, corresponding to 2N and 4N DNA, respectively.
(H) N:C volume ratio as a function of duration in interphase (DNA amount) for cells smaller than the sizer threshold: cells
25-35 µm diameter. The red dots indicate the peaks 2N to 4N in subfigure (E). A.U., arbitrary units.
(I) Mean values for N:C ratio for 2N and 4N DNA bins from (H). Shows N:C volume ratio at early and late interphase, corresponding to 2N and 4N DNA, respectively.
(J) N:C volume ratio as a function of DNA amount for small cells: those with a cell diameter of 23.5-25.5 µm. The dotted line indicates the threshold of N:C ratio adapted from Figure S3B in Jevtic and Levy, Curr Biol 2015. All cells are above this threhold.
(K) Fraction of transcriptionally active cells as a function of N:C ratio for small cells (23.5-25.5 µm cell diameter). Data were binned in 0.01 increments of N:C ratio. Many cells whose N:C ratio has surpassed the threshold remain inactive. 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 |