Fig. 1: Telomere elongation during pre-implantation embryogenesis is impaired by oxidative stress.
From: Telomere length in offspring is determined by mitochondrial-nuclear communication at fertilization
Mouse oocytes underwent in vitro fertilization (IVF) and embryos were collected at specific developmental stages at the times indicated (a) Created in BioRender. Gordon, Y. (2025) https://BioRender.com/u13t276. Telomere length (telomere/ Rn18s (2-ΔΔCt)) was measured by qPCR. Telomere length in individual oocytes/ embryos (b; n = 50 MII, n = 51 2 C, n = 57 4 C, n = 44 8 C, n = 77 blastocyst). Telomere length in dissected Inner Cell Mass (ICM) and Trophectoderm (TE) from the same blastocysts (c; n = 51). A whole blastocyst (d; upper) or isolated Inner Cell Mass (ICM) after immunosurgery (d; lower) to show purity of ICM cells (green, OCT4 + ) without TE cells (magenta, CDX2 + ). Telomere length in ICM from day 5 (D5, n = 16) and day 6 (D6, n = 21) blastocysts (e). MII oocytes were fertilized by IVF and cultured in vitro at either 5% or 20% oxygen (f) Created in BioRender. Gordon, Y. (2025) https://BioRender.com/x79j582. Telomere length in individual 8-cell embryos (g; n = 36 5% O2, n = 47 20% O2), morulae (h; n = 24 5% O2, n = 25 20% O2), and ICMs (h; n = 25 5% O2, n = 28 20% O2, i; n = 16 5% O2, n = 18 20% O2). Quantitative telomere FISH for telomere (green) with DAPI DNA stain (blue) in dissociated ICMs (j; left) and fluorescence per cell quantified (j; right; n = 271 nuclei from 30 ICMs derived from 4 mice per group, individual data points are plotted, horizontal lines are mean ± SEM). Violin plots show population distribution of telomere length, and horizontal lines are mean ± SEM (b, c, e, g-i). qPCR data was log transformed for statistical analysis. Statistical tests were: linear mixed-effects model (b); two-sided paired t-test (c), two-sided unpaired t-test (e, g, i, j); or two-way ANOVA (h). For (b) different letters indicate p < 0.05. For (c, h-j) *p < 0.02, ***p = 0.0004, ****p < 0.0001. For exact P values see Supplementary Table 1. Representative images shown, scale bar: 20 µm (d), 5 µm (j). Source data are provided as a Source Data File.
