Fig. 2

Expression of TgTP6.4 transgene in preimplantation embryos. a-f Transmitted light images with overlays from the confocal FITC channel to identify tauGFP in preimplantation embryos produced by crosses between WT, (C57BL × CBA/Ca)F1 females and hemizygous TgTP6.4 ^Tg/− males (a-c) and in those produced by crosses between hemizygous TgTP6.4 ^Tg/− females and (C57BL × CBA/Ca)F1 males (d-f). Images shown were captured during three separate time-lapse, embryo culture experiments (shown in a, b-c and d-f respectively). Arrows in (d-f) indicate two (BALB/c × A/J)F2 negative control embryos and the embryo marked with the letter ‘x’ remained at the 2-cell stage throughout the culture period so was excluded from the quantitative study. The scale bar in (a) (for a-f) = 100 μm. g, h Plots of pixel intensity (produced by tauGFP fluorescence) at different times during embryo culture, time-lapse experiments for preimplantation embryos produced by crosses between (C57BL × CBA/Ca)F1 females and hemizygous TgTP6.4 ^Tg/− males (g) and the reciprocal cross between hemizygous TgTP6.4 ^Tg/− females and (C57BL × CBA/Ca)F1 males (h). The time-lapse experiments shown are representative of two such experiments for each cross. Pixel intensity values for individual embryos are shown as points. Embryos were classified as TgTP6.4 ^Tg/− or TgTP6.4 ^−/− according to their pixel intensity at the end of the culture period and the mean value for each genotype is shown as a solid line (upper line is TgTP6.4 ^Tg/−). In (h) pixel intensities are also shown for two (BALB/c × A/J)F2 negative control embryos (lowest line in h). The red arrows below the x-axis indicate times when the time-lapse was interrupted, sometimes causing differences in pixel intensity. A repeated measures 2-way ANOVA for (g) showed significant differences overall for age, genotype and interaction (P < 0.0001 in each case) and Bonferroni multiple comparison post-tests for each age showed that genotype differences were significant at 37.5 h. (P < 0.01), 38 h. (P < 0.05), and all times thereafter (P < 0.01 to P < 0.0001). For (h), a repeated measures 2-way ANOVA comparing embryos with high and low tauGFP levels showed significant differences overall for age, genotype and interaction (P < 0.0001 in each case) and Bonferroni multiple comparison post-tests for each age showed that genotype differences were significant from 42.5 h. (for 42.5–44.5 h., P < 0.05; for 45.0 to 47.4 h., P < 0.01 to P < 0.0001; from 47.9 h., P < 0.0001). A repeated measures 2-way ANOVA comparing low tauGFP and (BALB/c × A/J)F2 negative control embryos showed significant differences overall for age (P = 0.0093) and genotype (P < 0.0001) but not the interaction (P = 0.1831) and Bonferroni multiple comparison post-tests for each age showed that genotype differences were significant at all ages (P < 0.05 to P < 0.0001) except for 38.5, 38.6 and 39.6 h