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Induction of germ cell-like cells from deleted in azoospermia-like enhanced green fluorescent protein gene knock-in chicken somatic cells via transgenic expression of pluripotency and germ cell-specific transcription factors

  • Bo Ram Lee (Animal Biotechnology and Genomics Division, National Institute of Animal Science, Rural Development Administration) ;
  • Hyeon Yang (Animal Biotechnology and Genomics Division, National Institute of Animal Science, Rural Development Administration) ;
  • Sun Keun Jung (Animal Biotechnology and Genomics Division, National Institute of Animal Science, Rural Development Administration) ;
  • Sung June Byun (Poultry Research Center, National Institute of Animal Science, Rural Development Administration) ;
  • Tae Sub Park (Graduate School of International Agricultural Technology and Institute of Green-Bio Science and Technology, Seoul National University)
  • Received : 2025.04.05
  • Accepted : 2025.07.13
  • Published : 2026.01.01

Abstract

Objective: Germ cell identity is regulated by the coordinated action of multiple key transcription factors during embryonic development, which includes the induction and control of germ-line-specific gene expression. The expression of DEAD-box helicase 4 (DDX4) and deleted in azoospermia-like (DAZL) genes in chickens plays a pivotal role in germplasm formation and the specification of germ cell lineage from a totipotent genome. This study aimed to investigate the regulatory mechanisms underlying germ cell fate determination. Methods: Large-scale gene expression profiling was conducted to screen and select critical transcription factors. This analysis identified differentially expressed genes in chicken primordial germ cells (PGCs), comprising 1,020 transcription factors. Additionally, we generated a chicken DF1 cell line featuring an enhanced green fluorescent protein (eGFP) reporter precisely knocked into the transcriptional start site of the DAZL gene using the CRISPR-Cas9 system, enabling real-time monitoring of DAZL expression during reprogramming. Results: Through analysis of transcription factor binding sites within approximately 10 kb upstream regions of DDX4 and DAZL, resulting in the selection of 10 candidate transcription factors for germ cell induction. Subsequently, the ten transcription factors identified as regulators of germ cell identity were transduced into the DAZL-knock-in eGFP DF1 cells. This approach led to the successful induction of eGFP-expressing cells in vitro, driven by the endogenous DAZL promoter. We conducted further characterization of these cells to confirm their germ cell-specific properties. Conclusion: Our findings offer new insights into the transcriptional regulation of chicken germ cells by identifying key factors that activate DAZL expression. These results indicated valuable opportunities for advancing germ cell induction from somatic cells, with potential applications of in vitro models for studying germ cell-specific gene regulatory pathways in avian species.

Keywords

Acknowledgement

This research was supported by the "Cooperative Research Program for Agriculture Science and Technology Development (Project No. PJ01481702)" from the Rural Development Administration (RDA), Republic of Korea, and by the Basic Science Research Program through a grant from the National Research Foundation (NRF) of Korea, funded by the Ministry of Education (Grant No. NRF-2017R1D1A1B03029512).

References

  1. Donovan PJ. The germ cell-the mother of all stem cells. Int J Dev Biol 1998;42:1043-50.
  2. Lee BR, Rengaraj D, Choi HJ, Han JY. A novel F-box domain containing cyclin F like gene is required for maintaining the genome stability and survival of chicken primordial germ cells. FASEB J 2020;34:1001-17. https://doi.org/10.1096/fj.201901294R
  3. Lee SI, Lee BR, Hwang YS, et al. MicroRNA-mediated posttranscriptional regulation is required for maintaining undifferentiated properties of blastoderm and primordial germ cells in chickens. Proc Natl Acad Sci USA 2011;108: 10426-31. https://doi.org/10.1073/pnas.1106141108
  4. Jin SD, Lee BR, Hwang YS, Lee HJ, Rim JS, Han JY. Regulatory elements and transcriptional control of chicken vasa homologue (CVH) promoter in chicken primordial germ cells. J Anim Sci Biotechnol 2017;8:6. https://doi.org/10.1186/s40104-016-0133-5
  5. Tsunekawa N, Naito M, Sakai Y, Nishida T, Noce T. Isolation of chicken vasa homolog gene and tracing the origin of primordial germ cells. Development 2000;127:2741-50. https://doi.org/10.1242/dev.127.12.2741
  6. Lee HC, Choi HJ, Lee HG, Lim JM, Ono T, Han JY. DAZL expression explains origin and central formation of primordial germ cells in chickens. Stem Cells Dev 2016;25:68-79. https://doi.org/10.1089/scd.2015.0208
  7. Tang WWC, Kobayashi T, Irie N, Dietmann S, Surani MA. Specification and epigenetic programming of the human germ line. Nat Rev Genet 2016;17:585-600. https://doi.org/10.1038/nrg.2016.88
  8. Extavour CG, Akam M. Mechanisms of germ cell specification across the metazoans: epigenesis and preformation. Development 2003;130:5869-84. https://doi.org/10.1242/dev.00804
  9. Seydoux G, Braun RE. Pathway to totipotency: lessons from germ cells. Cell 2006;127:891-904. https://doi.org/10.1016/j.cell.2006.11.016
  10. Megosh HB, Cox DN, Campbell C, Lin H. The role of PIWI and the miRNA machinery in Drosophila germline determination. Curr Biol 2006;16:1884-94. https://doi.org/10.1016/j.cub.2006.08.051
  11. Lee BR, Yang H, Byun SJ, Park TS. Research note: development of a chicken experimental model platform for induced pluripotent stem cells by using CRISPR/Cas9-mediated NANOG knock-in reporter DF1 cells. Poult Sci 2023;102:102425. https://doi.org/10.1016/j.psj.2022.102425
  12. Lu Y, West FD, Jordan BJ, et al. Induced pluripotency in chicken embryonic fibroblast results in a germ cell fate. Stem Cells Dev 2014;23:1755-64. https://doi.org/10.1089/scd.2014.0080
  13. Cheng H, Shang D, Zhou R. Correction to: germline stem cells in human. Signal Transduct Target Ther 2022;7:385. https://doi.org/10.1038/s41392-022-01258-7
  14. Shono M, Kishimoto K, Hikabe O, et al. Induction of primordial germ cell-like cells from common marmoset embryonic stem cells by inhibition of WNT and retinoic acid signaling. Sci Rep 2023;13:3186. https://doi.org/10.1038/s41598-023-29850-z
  15. Park TS, Park J, Lee JH, Park JW, Park BC. Disruption of G0/G1 switch gene 2 (G0S2) reduced abdominal fat deposition and altered fatty acid composition in chicken. FASEB J 2019;33:1188-98. https://doi.org/10.1096/fj.201800784R
  16. Kim GD, Lee JH, Song S, et al. Generation of myostatinknockout chickens mediated by D10A-Cas9 nickase. FASEB J 2020;34:5688-96. https://doi.org/10.1096/fj.201903035R
  17. Kang KS, Shin SP, Ha IS, et al. Production of chickens with green fluorescent protein-knockin in the Z chromosome and detection of green fluorescent protein-positive chicks in the embryonic stage. Anim Biosci 2023;36:973-9. https://doi.org/10.5713/ab.22.0405
  18. Park TS. Gene-editing techniques and their applications in livestock and beyond. Anim Biosci 2023;36:333-8. https://doi.org/10.5713/ab.22.0383
  19. Lee BR, Kim H, Park TS, et al. A set of stage-specific gene transcripts identified in EK stage X and HH stage 3 chick embryos. BMC Dev Biol 2007;7:60. https://doi.org/10.1186/1471-213X-7-60
  20. Lee BR, Ock SA, Park MR, Lee MG, Byun SJ. Establishing porcine jejunum-derived intestinal organoids to study the function of intestinal epithelium as an alternative for animal testing. J Anim Reprod Biotechnol 2024;39:2-11. https://doi.org/10.12750/JARB.39.1.2
  21. Robinson MD, McCarthy DJ, Smyth GK. edgeR: a bioconductor package for differential expression analysis of digital gene expression data. Bioinformatics 2010;26:139-40. https://doi.org/10.1093/bioinformatics/btp616
  22. Cartharius K, Frech K, Grote K, et al. MatInspector and beyond: promoter analysis based on transcription factor binding sites. Bioinformatics 2005;21:2933-42. https://doi.org/10.1093/bioinformatics/bti473
  23. Shen WK, Chen SY, Gan ZQ, et al. AnimalTFDB 4.0: a comprehensive animal transcription factor database updated with variation and expression annotations. Nucleic Acids Res 2023;51:D39-45. https://doi.org/10.1093/nar/gkac907
  24. Saffman EE, Lasko P. Germline development in vertebrates and invertebrates. Cell Mol Life Sci 1999;55:1141-63. https://doi.org/10.1007/s000180050363
  25. Wolke U, Weidinger G, Köprunner M, Raz E. Multiple levels of posttranscriptional control lead to germ line-specific gene expression in the zebrafish. Curr Biol 2002;12:289-94. https://doi.org/10.1016/s0960-9822(02)00679-6
  26. Choi HJ, Jin SD, Rengaraj D, Kim JH, Pain B, Han JY. Differential transcriptional regulation of the NANOG gene in chicken primordial germ cells and embryonic stem cells. J Anim Sci Biotechnol 2021;12:40. https://doi.org/10.1186/s40104-021-00563-5
  27. Suzuki K, Kwon SJ, Saito D, Atsuta Y. LIN28 is essential for the maintenance of chicken primordial germ cells. Cells Dev 2023;176:203874. https://doi.org/10.1016/j.cdev.2023.203874 
  28. Okuzaki Y, Kaneoka H, Suzuki T, et al. PRDM14 and BLIMP1 control the development of chicken primordial germ cells. Dev Biol 2019;455:32-41. https://doi.org/10.1016/j.ydbio.2019.06.018
  29. Hansen CL, Pelegri F. Primordial germ cell specification in vertebrate embryos: phylogenetic distribution and conserved molecular features of preformation and induction. Front Cell Dev Biol 2021;9:730332. https://doi.org/10.3389/fcell.2021.730332
  30. He Y, Zuo Q, Edwards J, et al. DNA methylation and regulatory elements during chicken germline stem cell differentiation. Stem Cell Reports 2018;10:1793-806. https://doi.org/10.1016/j.stemcr.2018.03.018
  31. Zhang M, Chambers I. Segregation of the mouse germline and soma. Cell Cycle 2019;18:3064-71. https://doi.org/10.1080/15384101.2019.1672466
  32. Collier B, Gorgoni B, Loveridge C, Cooke HJ, Gray NK. The DAZL family proteins are PABP‐binding proteins that regulate translation in germ cells. EMBO J 2005;24:2656-66. https://doi.org/10.1038/sj.emboj.7600738