Shanghai Children’s Hospital, Shanghai Institute of Medical Genetics, Shanghai Jiao Tong University School of Medicine, China
Abstract: Embryonic stem cells (ESCs) are capable of developing into the three germ layers and germ cells, but cannot generate trophectoderm or extraembryonic lineages, which are recognized as pluripotent. However, ~1% of ESCs, referred to as 2-cell-like cells (2CLCs), resemble 2-cell-stage blastomeres and maintain a totipotent-like capacity to produce both lineages. Whether and how pluripotent ES cells can be reprogrammed into a stable totipotent state remain formidable challenges in current researches. In this study, we discovered that deletion of the Ybx1 gene effectively reprograms mESCs into stable totipotent like state, which can be maintained over long-term culture in vitro. Ybx1-deficient mESCs exhibit key characteristics of 2-cell embryos, including expression of totipotent markers and similar transcriptomic profiles, such as the Zscan4 cluster transcripts and endogenous retrovirus (ERVs) MERVL. In vivo chimera formation assays further revealed that Ybx1-null mESCs possess both embryonic and extraembryonic developmental potentials at the single-cell level. Finally, we demonstrated that Ybx1 functions as a transcriptional repressor of Zscan4, a factor essential for totipotency establishment. Thus, our study identifies Ybx1 as a novel regulator of stable 2CLC totipotent state establishment, representing a component of a previously unrecognized 2C-like transcriptional network, thereby opening up new avenues for future clinical applications and therapeutic strategies.
Funding Source: National Key Research & Development Program of China (2023YFC2705700,2024YFC2707002,2024YFC2707001), National Natural Science Foundation of China (82271890)
