Journal: Poultry Science

Article Title: High genotoxicity of CRISPR/Cas9 versus limited efficacy of CRISPRi in chicken primordial germ cells

doi: 10.1016/j.psj.2026.106722

Figure Lengend Snippet: CRISPR/Cas9 induces DNA damage and apoptosis in PGCs. (A) Flow cytometry analysis 24 h after electroporation, quantifying the proportion of Annexin V + /PI + cells. The horizontal axis indicates PI and the vertical axis Annexin V. The upper-left quadrant (Annexin V + /PI + ) represents late apoptotic cells, and the lower-right quadrant (Annexin V + only) represents early apoptotic cells. Upper panels: results after electroporation with Cas9 + various gRNAs; lower panels: results with dCas9 + various gRNAs. (B) Bar graph of Annexin V + /PI + percentages across groups. Cas9 editing induced a highly significant increase in late apoptosis. (C) γ-H 2 AX foci (green) detected by immunofluorescence 24 h after electroporation. Foci appear as discrete nuclear puncta; nuclei are counterstained with DAPI (blue). Scale bar = 10 µm. (D) Quantification of γ-H 2 AX foci per cell. Cas9 targeting resulted in a significant increase in γ-H 2 AX foci per cell, whereas dCas9 with sgRNA did not. Statistical significance determined by one-way ANOVA (p-values are indicated in the figure).

Article Snippet: After another centrifugation, the supernatant was removed and cells were resuspended in 500 μL of 1× Annexin V Binding Buffer (from Annexin V-FITC/PI Apoptosis Kit, Elabscience E-CK-A211).

Techniques: CRISPR, Flow Cytometry, Electroporation, Immunofluorescence

Journal: Poultry Science

Article Title: High genotoxicity of CRISPR/Cas9 versus limited efficacy of CRISPRi in chicken primordial germ cells

doi: 10.1016/j.psj.2026.106722

Figure Lengend Snippet: PGCs are more sensitive to DNA double-strand breaks than somatic cells. (A) Cell viability curves after 24 h treatment with increasing concentrations of etoposide (ETP; x-axis shows log 10 [ETP]). PGC viability dropped sharply even at low ETP doses, whereas CEF cells were more tolerant (viability data are mean ± SD of triplicates). (B) Apoptosis detection in PGCs treated with low-dose ETP. The proportion of Annexin V + /PI + cells (late apoptosis) was significantly elevated even at 0.03 µM ETP. (C) Western blot analysis of γ-H 2 AX protein in PGCs treated with varying ETP concentrations (left panel; β-actin as loading control). The bar graph (right) shows the ratio of γ-H 2 AX to β-actin band intensity, with a marked increase at 3 µM ETP (p-values are indicated in the figure). (D) Quantification of γ-H 2 AX foci per cell in THP-1 cells, male PGCs, and female PGCs after exposure to X-ray doses of 0, 2, 4, 6, and 8 Gy. After 48 h recovery, γ-H 2 AX foci increased significantly with higher radiation in THP-1, male PGCs, and female PGCs. Female PGC data points are red squares; male PGCs are blue squares; THP-1 are black circles. (E) Cell-cycle distribution of male vs. female PGCs after DNA damage. PGCs were irradiated (2, 4, 6 Gy), cultured 48 h, and analyzed by flow cytometry for cell-cycle phase (propidium iodide staining). Stacked bars show the percentage of cells in G 0 G 1 , S, and G 2 /M phases in untreated vs. irradiated cells. After damage, female PGCs predominantly arrested in G 2 /M (increased G 2 fraction), whereas male PGCs accumulated in S phase. Statistical significance by one-way ANOVA (p-values are indicated in the figure).

Article Snippet: After another centrifugation, the supernatant was removed and cells were resuspended in 500 μL of 1× Annexin V Binding Buffer (from Annexin V-FITC/PI Apoptosis Kit, Elabscience E-CK-A211).

Techniques: Western Blot, Control, Irradiation, Cell Culture, Flow Cytometry, Staining