Conclusions
These observations indicate that SMAD3 is a key factor for SSCs transformation, and an unknown event is required to activate SMAD3 as the prerequisite for SSCs reprogramming, which may occur in the long-term culture of SSCs. This study demonstrates the connection of p53 and pluripotency-associated factors, providing new insight for understanding the mechanisms of SSCs reprogramming and germline tumorigenesis.
Methods
The chromatin accessibility and differentially expressed genes (DEGs) were analysed in p53+/+ and p53-/- SSCs using the Assay for Transposase-Accessible Chromatin with high-throughput Sequencing (ATAC-seq) and RNA-sequencing (RNA-seq), to explore the connection of p53 and cell fate at chromosomal level.
Results
Several transcription factors (TFs), such as CTCF, SMAD3 and SOX2, were predicted as important factors mediating the transformation. Molecular evidence suggested that SMAD3 efficiently promoted pluripotency-associated gene expression both in fresh and long-term cultured SSCs. However, p53 knockout (KO) is insufficient to induce SMAD3 expression in SSCs. Conclusions: These observations indicate that SMAD3 is a key factor for SSCs transformation, and an unknown event is required to activate SMAD3 as the prerequisite for SSCs reprogramming, which may occur in the long-term culture of SSCs. This study demonstrates the connection of p53 and pluripotency-associated factors, providing new insight for understanding the mechanisms of SSCs reprogramming and germline tumorigenesis.