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Zygote

Real pictures of the zygote delivered by gather.site, each with its paper.

12 pictures and 11 papers.

Gallery

Immunofluorescence staining of F-actin with phalloidin and DNA with DAPI, depicting the F-actin meshwork in zygotes at different hours post insemination. Scale bar: 20 µm. The white dashed circle indicates pronuclei. (human; Figure 2, panel A (IF of human zygotes at multiple hours post insemination; rows 17-404 of figure).)

Zhang, Cui, Yang et al 2024, EMBO Reports · CC BY 4.0

Tcf12-maternal deletion impairs separation of sister chromatids, induced cell cycle delay of zygote. (A) Detection of DNA replication in WT and Tcf12 female-/male+ zygotes after IVF using 5-ethynyl-2'-deoxy-uridine (EdU) incorporation. PB: Polar body. The rates of representative oocytes are shown in the corners. Scale bar, 50 um. Adapted: fluorescence panel A only; quantification panels B-E and H3S10 IF panel F excluded. (mouse (IVF zygotes, WT and Tcf12 maternal-knockout); FIGURE 5, panel A only (EdU fluorescence of zygotes; quantification panels B-E and H3S10 IF panel F excluded).)

Cao, Zhang, Deng et al 2026, Cell Proliferation · CC BY 4.0

Pronuclear assessment and time-lapse development of embryos from the reported cycle. A Representative image of the five-pronuclear (5PN) zygote; arrows indicate the five pronuclei. B Time-lapse images of embryos #1-#5 at key developmental time points: pronuclear stage (PN), 2-cell (t2), 4-cell (t4), 8-cell (t8), and blastocyst (tB) (times annotated relative to ICSI, t0). Embryo #1 arrested at the early blastocyst stage (Gardner stage 2), Embryo #2 arrested after the PN stage, #3 arrested at cleavage stage, whereas embryos #4-#5 progressed to blastocyst (human (clinical IVF cycle, ICSI-fertilized zygotes including a 5PN case resulting in live birth); Fig. 1.)

Gomes, Nicolielo, Lourenco et al 2026, Journal of Assisted Reproduction and Genetics · CC BY 4.0

Aluminum exposure disrupts microtubule and actin filament structures in mouse zygotes (A) Typical images of the distribution of alpha-tubulin in control and AlCl3-treated mouse zygotes by immunofluorescence staining. Green, alpha-tubulin; blue, DNA. Scale bars, 20 um. (B) Relative fluorescence intensity of alpha-tubulin around female and male pronuclei. Female pronucleus: Control, n = 42; AlCl3, n = 52, *** p < 0.001; Male pronucleus: control, n = 42; AlCl3, n = 52, *** p < 0.0005. (C) Typical images of Ac-tubulin staining in control and treatment groups by immunofluorescence staining. Green, Ac-tubulin; blue, DNA. Scale bars, 20 um. (D) Relative fluorescence intensity of Ac-tubulin. Control, n = 56; AlCl3, n = 50, **** p < 0.0001. (E) Typical distribution of actin in control and AlCl3-treated mouse zygotes by fluorescence staining. Red, actin; blue, DNA. Scale bars, 20 um. (F) Relative fluorescence intensity of cortical actin and cytoplasmic actin. Cortical actin: control, n = 42; AlCl3, n = 43, ** p < 0.01; cytoplasmic actin: control, n = 41; AlCl3, n = 44, *** p < 0.0005. Data are presented as mean +/- SEM. (mouse (fertilized mouse zygotes; control and AlCl3 aluminum chloride treated groups); Figure 2.)

Yu, Ke, Wu et al 2026, iScience · CC BY 4.0

Inhibition of H4K20me1 in early embryos leads to arrest of embryonic developmental processes. (A) Immunofluorescence images showing H4K20me1 (red), DAPI-stained nuclei (cyan), and the merged signals in mouse oocytes and early embryos. Scale bar: 20 um. (B) Mean fluorescence values of H4K20me1 levels in mouse oocytes and early embryos. The experiments were independently repeated three times, and the total number of embryos analyzed per developmental stage was as follows: GV oocyte (23), MII oocyte (29), zygote (32), 2-cell (26), 4-cell (36), 8-cell (47), and blastocyst (30). Data are presented as mean +/- SEM. (C) Representative images of embryos from the Control, DMSO control, 5 uM UNC0379, and 7.5 uM UNC0379 groups are shown at the indicated time points after treatment. Scale bar: 100 um. (D) The proportions of embryos at each stage in the standard medium control, DMSO control, 5 uM UNC0379, and 7.5 uM UNC0379 groups. Embryos were cultured in vitro and assessed at the indicated time points: zygote (0 h), 2-cell (16 h), 4-cell (40 h), 8-cell (48 h), and blastocyst (72-96 h). The experiment was independently repeated three times. Total embryo numbers per group: Control, n = 89; DMSO, n = 72; 5 uM UNC0379, n = 88; 7.5 uM UNC0379, n = 90. Data are shown as mean +/- SEM. (E) Representative images of embryos from the Control, 5 uM UNC0379, 7.5 uM UNC0379, and rescue groups are shown at the indicated time points after treatment. Scale bar: 100 um. (Figure 5.)

Meng, He, Fang et al 2026, EMBO Reports · CC BY 4.0

PARP7 knockdown leads to developmental delay at the two-cell stage and reduces blastocyst rate. (A) Schematic diagram of the Trim-Away strategy for acute degradation of PARP7. Embryos were microinjected with anti-PARP7 antibody and mCherry-Trim21 mRNA at 6 h post-fertilization (hpf). (B) Representative immunofluorescence images showing efficient degradation of PARP7 protein in 2-cell stage embryos. PARP7 is green, and DNA was stained with DAPI (blue). Scale bar: 20 um. (C) Representative bright-field images of control and PARP7-KD (knockdown) embryos during culture from 6 to 96 hpf. Scale bar: 200 um. (D) Embryos at specified developmental stages from control and PARP7-KD groups were quantified at the indicated time points (N>60 per group from three independent experiments). (E) Representative time-lapse morphological tracking of embryos. The red box highlights the developmental arrest during the 2- to 4-cell transition in PARP7-KD embryos compared to controls. Scale bar: 50 um. (F) Stacked bar chart showing the percentage of embryos at each developmental stage corresponding to the experiment in panel E. (G) RT-qPCR analysis of Minor ZGA genes (left) and Major ZGA genes (right) in 2-cell embryos. PARP7 deficiency significantly downregulated the expression of key ZGA markers. (H, I) Representative immunofluorescence images and quantitative analysis of RNA polymerase II C-terminal domain serine 2 (P-Ser2) phosphorylation (H) and serine 5 (P-Ser5) phosphorylation (I) in 2-cell embryos. PARP7-KD significantly reduced P-Ser2 intensity but not P-Ser5 intensity. Scale bar: 20 um. Data are presented as mean +/- SEM. n = 3 independent biological replicates. (mouse (control and PARP7-KD mouse embryos from zygote to blastocyst stage); FIGURE 2.)

Cao, Zhang, Chen et al 2026, Advanced Science · CC BY 4.0

Unequal translation of Rbbp7 leads to an asymmetric protein expression of RBBP7. (a) Immunofluorescent staining of RBBP7 in early (2CE), mid (2CM), and late (2CL) 2-cell embryos. The yellow triangles indicate blastomeres with relatively less RBBP7. Scale bar, 20 um. (b) Immunofluorescent staining of RBBP7 in early, mid, and late 2-cell embryos. Scale bar, 20 um. (c) Quantification of the difference of RBBP7 intensity between two blastomeres in 2CL embryos. RBBP7 intensity was normalized to DNA intensity. Blastomeres are labeled as B1 and B2 according to decreasing fluorescent intensity. (Fig. 2.)

Ju, Han, Zhang et al 2026, Cell Discovery · CC BY 4.0

Divergence in pericentric H2AK119ub1 heterochromatin and PRC1 recruitment. ( A ) Schematic showing PRC1 recruitment to DNA via the AT-hook of its CBX2 subunit, which binds into the minor groove of A/T runs present in satellite DNA. Chromodomain labeled as CD. ( B ) Mouse zygotes are generated by injecting a M. musculus egg arrested in meiosis II with the sperm of mouse species with divergent pericentric satellite DNAs. ( C to E ) Zygotes generated with sperm from the indicated species were arrested in mitosis with a kinesin-5 inhibitor (STLC, C) or by APC/C inhibition (proTAME, D) and then fixed and stained for H2AK119ub1 or RNF2 (green), H3K9me3 (magenta) to mark maternal M. musculus chromosomes, and DAPI (gray). Graphs (E) show average H2AK119ub1 ( n = 103 to 164, N = 2) and RNF2 ( n = 152 to 160, N = 2) intensities along M. musculus (red), M. caroli (yellow), and M. pahari (blue) paternal chromosomes. Both M. musculus and M. caroli chromosomes have significantly higher H2AK119ub1 intensity than M. pahari chromosomes within the first two microns (*** P < 0.001). Images are max intensity z-projections. Scale bars, 10 or 1 um (insets). (Fig. 1.)

Lamelza, Parrado, Leara et al 2026, Science Advances · CC BY 4.0

LincSAKP depletion results in developmental arrest at the 8-cell stage with effects on ZGA initiation. (A) Depletion of LincSAKP does not affect DNA integrity and replication. BrdU was used to visualize S and G2 phases. Aphidicolin-treated embryos were arrested at the S phase without DNA replication. There was no difference in fluorescence intensity between NC ASO and LincSAKP ASO-1. Embryos were collected at pPA 72 h (8-cell stage) for immunofluorescence analysis. Scale bar, 100 um. Data are shown as mean +/- SEM. (B) LincSAKP ASO-1-mediated depletion was associated with reduced DNase I-TUNEL fluorescence intensity and nuclear diameter in 8-cell-stage embryos. Scale bar, 100 um. Data are shown as mean +/- SEM. (C) Nascent RNA transcription during ZGA was detected by EU labeling after LincSAKP-ASO-1 depletion. EU was added to the culture medium at pPA 64 h, and EU signals were detected at pPA 72 h. Scale bar, 100 um. (Figure 3.)

He, Zhang, Zhang et al 2026, Cells · CC BY 4.0

The zygote with two pre-convergence pronuclei has a typical PC and atypical DC (24 h after fertilization). (a) General view of the zygote at low magnification; sperm and egg nuclei are designated as male and female, respectively; (b) apical region of the sperm flagellum near male pronucleus; (c, d) two sections at high magnification; (e) schematic diagram of the structure of the centrosome at this stage. cMT - central MT of flagellum; DF - dense fibers; Fl - flagellum; M - mitochondria of the sperm; PrC - proximal centriole; pMT - MT of peripheral doublets; SC - striated column. Scale bars: (a) 20 um; (b) 5 um; (c, d) 0.3 um. (bovine (in vitro fertilized bovine zygote at 24 h post-fertilization); Figure 2.)

Uzbekov, Singina, Shedova et al 2023, Cells · CC BY 4.0

Creatine metabolism specifically regulates TE formation. A, representative images of 8-cell embryos, morulae, and blastocysts in control, Cr, CCr, and rescue (CCr + Cr) groups. Scale bar: 100 um. B, morula rates in each group. C, Blastocyst rates in each group. Control (n = 53), Cr (n = 51), CCr (n = 52), rescue (n = 49). D, Immunofluorescence staining images of SOX2, CDX2, and DAPI in blastocysts from each group. Scale bar: 50 um. E-G, total, TE, and ICM cell numbers in blastocysts from each group. H, relative mRNA expression levels of Sox2, Cdx2, and Pcna in blastocysts. I, relative mRNA expression levels of Elf5 and Gata3 in blastocysts. J, immunofluorescence staining images of SOX2, CDX2, and DAPI in blastocysts from control and CCr-treated groups in vivo. Scale bar: 50 um. CDX2, caudal type homeobox 2; SOX2, SRY-box transcription factor 2. ICM, inner cell mass; TE, trophectoderm. (Figure 2.)

Chen, Pan, Qin et al 2026, The Journal of Biological Chemistry · CC BY 4.0

Papers

He T, Zhang S, Zhang S, Liu D, Li H, Song J, et al. A Novel SINE Transposable Element-Associated lncRNA Regulates Zygotic Genome Activation in Porcine Parthenogenetically Activated Embryos. Cells. 2026;15:1707. PMID: 42782807.
Ju LF, Han X, Zhang D, Xu HJ, Jia S, Liu MX, et al. Asymmetric RBBP7 regulates the first cell fate decision of early mammalian embryos. Cell Discov. 2026;12:60. PMID: 42608389.
Lamelza P, Parrado M, Leara K, Balboula AZ, Keane TM, Lampson MA. Satellite DNA sequence dictates pericentromere heterochromatin formation and function. Sci Adv. 2026;12:eady2267. PMID: 42455957.
Cao G, Zhang Z, Chen A, Liu Y, Lin Y, Yu L, et al. NAD+ Metabolism Licenses Zygotic Genome Activation via PARP7-Mediated ADP-Ribosylation of UHRF1 in Mouse Early Embryos. Adv Sci (Weinh). 2026;13:e76136. PMID: 42294794.
Chen X, Pan B, Qin J, Wei Y, Du K, Ning A, et al. Creatine metabolism regulates trophectoderm formation in early mouse embryos via an energy-cytoskeleton-YAP axis. J Biol Chem. 2026;302:113147. PMID: 42155769.
Gomes C, Nicolielo M, Lourenço B, Reis DG, Aiello B, Reis I, et al. Live birth following transfer of a euploid blastocyst derived from a 5PN zygote: a case report. J Assist Reprod Genet. 2026;43:2059-2063. PMID: 42141313.
Yu XT, Ke XH, Wu ZJ, Fu ZH, Ma RJ, Wu X, et al. Aluminum exposure impairs nuclear envelope breakdown for mouse zygote formation. iScience. 2026;29:115807. PMID: 42111199.
Meng X, He Z, Fang D, Li W, Guo J, Lu J, et al. The reprogramming and function of H4K20me1 during early embryo development. EMBO Rep. 2026;27:3050-3077. PMID: 42020515.
Cao LR, Zhang C, Deng ZQ, Qiu YX, Zhang Z, Fan HY, et al. Transcription Factor TCF12-Mediated Maternal Gene Expressions in Mouse Oocyte Are Prerequisites of Successful Fertilisation and Zygotic Genome Activation. Cell Prolif. 2026;59:e70110. PMID: 40754719.
Zhang H, Cui Y, Yang B, Hou Z, Zhang M, Su W, et al. CHK1 controls zygote pronuclear envelope breakdown by regulating F-actin through interacting with MICAL3. EMBO Rep. 2024;25:4876-4897. PMID: 39358552.
Uzbekov R, Singina GN, Shedova EN, Banliat C, Avidor-Reiss T, Uzbekova S. Centrosome Formation in the Bovine Early Embryo. Cells. 2023;12:1335. PMID: 37174735.