Fine Tuning of Histone Demethylase KDM6A/B Improves the Development of Nuclear Transfer Embryo (2018)
Figure 3

Figure. 3 Abnormal H3K27me3 modification of SCNT embryos at the 2-cell stage.

A. Immunofluorescence images of ICSI, SCNT-tdTomato+ and SCNT-tdTomato- embryos. Embryos approximately 26hr after activation were fixed and processed for immunostaining with antibodies to H3K27me3 and Gag protein. ICSI embryos produced by MERVL::tdTomato sperm from the littermates of male mice. The images are representative examples of the quantification shown in Fig 3B. Representative images from ≥ 128 embryos analyzed in five independent micromanipulations are shown. Scale bar, 20 μm.

B. Percentage of 2-cell ICSI and SCNT embryos with strong H3K27me3 staining and moderate staining (left). Numbers of the total embryos analyzed from five independent micromanipulations are shown in the bars. Boxplots (right) for relative intensities of H3K27me3 from five independent experiments for each expression as in Fig 3A. Error bars, s.e.m., ***P < 0.001 by two-tailed Student's  t-test.

C. Western blot results showing H3K27me3 levels in SCNT and ICSI embryos. α-Tubulin (TUBB) was blotted as a loading control. The Ponceau S staining demonstrates equivalent loading of each lane are shown in Appendix Fig S3E.

D. Representative immunofluorescent staining of H3K27me3 in ICSI embryos at the 1-cell stage. ICSI 1-cell embryos are characterised by the visualisation of two distinct pronuclei (2PN) 6 hours after sperm injection. H3K27me3 enrichment in the female-PN. The identity of the pronuclei was determined by their size and position relative to the polar body. Representative images from ≥ 95 embryos analyzed in four independent micromanipulations are shown. The optical Z-section series images are shown in Appendix Fig S3G. ♂ and ♀ indicated the male and female, respectively. SY, syngamy. Scale bar, 20 μm.

E. Representative immunofluorescent staining of H3K27me3 in SCNT embryos at the 1-cell stage. H3K27me3 enrichment in the SCNT embryos were observed with either 1 pseudo-pronucleus (1PPN), bipseudo-pronucleus (2PPN), or tripseudo-pronucleus (3PPN). BA, before activation; AA, after activation. Representative images from ≥ 55 embryos analyzed in three independent micromanipulations are shown. Scale bar, 20 μm.

F. Dynamic appearance of H3K27me3 during early preimplantation development. Shown are representative images of embryos stained with DNA and H3K27me3. Negative staining of H3K27me3 could be observed in ICSI and SCNT-tdTomato+ embryo at morula stage. Representative images from ≥ 83 embryos analyzed in four independent micromanipulations are shown. Scale bar, 20 μm.

G. Representative images of H3K27me3 immunostainings on bovine intraspecies SCNT embryos. IVF-derived bovine embryos were used as a control for comparison. These images are representative examples of the quantification shown in Fig 3H. Representative images from ≥ 100 embryos analyzed in four independent micromanipulations are shown; Scale bar, 20 μm.

H. The bar chart shows the percentages of strong and moderate H3K27me3 modifications of bovine embryos. Numbers of the total embryos analyzed from four independent micromanipulations are shown in the bars.