Figure 5. Depletion of maternal TET3 in zygotes enhances zygotic transcription.

(a) Representative images showing accumulation of incorporated 5EU in zygotes derived from oocytes of [Zp3-cre, Tet3^F/+] or [Zp3-cre, Tet3^F/–] female mice. Zygotes were pulse-labeled with 5EU from 4 to 6, 8, 10, or 12 hpi, incorporated 5EU was then observed (red in merged images). Pronuclei were revealed by staining of DNA with Sytox (green in merged images). Dashed circles, ♂, and ♀ indicate the rim of the zygote, the paternal pronucleus, and the maternal pronucleus, respectively. (b,c) The signal intensity for incorporated 5EU in the paternal and maternal pronuclei of zygotes derived from oocytes of [Zp3-cre, Tet3^F/–] (4–8 hpi, n = 11; 4–10 hpi, n = 15; 4–12 hpi, n = 15) or [Zp3-cre, Tet3^F/+] (4–8 hpi, n = 9; 4–10 hpi, n = 11; 4–12 hpi, n = 10) female mice was quantified, normalized by that of Sytox, and expressed relative to the normalized value for the paternal pronucleus of zygotes (4–8 hpi) derived from oocytes of [Zp3-cre, Tet3^F/+] females. The overall mean values and 95% CIs are shown in (b), and the average difference (and its 95% CI) in the normalized values between zygotes derived from oocytes of [Zp3-cre, Tet3^F/–] female mice and those derived from oocytes of [Zp3-cre, Tet3^F/+] females is indicated in (c). Normality and homoscedasticity of the data were verified by the Shapiro-Wilk test (α = 0.05) and F test (α = 0.05), respectively. The P values were determined by the two-sided Student’s t test, with the exception of that indicated by the asterisk, which was determined by the two-sided Welch’s t test because of unequal sample variance.