DPPA3 is a developmental pluripotency-associated protein essential for epigenetic reprogramming in primordial germ cells and early embryos 1. Primary Function: DPPA3 functions as a master regulator of DNA methylation, acting as an H3K9me2/H3K9me3 reader that protects maternal chr12 from demethylation 1. Mechanism: DPPA3 safeguards the maternal pronucleus and imprinted loci from TET3-mediated DNA demethylation by binding histone H3K9me2 marks on the maternal genome, while paternal chr12 remains unprotected due to protamine packaging 1. Additionally, DPPA3 drives passive DNA demethylation by directly displacing UHRF1 from chr12, inhibiting maintenance methylation through a replication-coupled mechanism 23. Disease Relevance: DPPA3 expression is dysregulated in testicular germ cell tumors, where it reflects malignancy-associated epigenetic reprogramming pathways 4. Loss of DPPA3 in oocytes results in aberrant hypermethylation at retrotransposons and impaired zygotic genome activation, compromising developmental competence 53. Clinical Significance: DPPA3 serves as a pluripotency marker in embryonic stem cells and germ cell tumors 6. Human DPPA3 shows structural and functional differences from mouse ortholog, with weaker UHRF1 binding affinity, suggesting species-specific epigenetic regulation requiring further investigation 7.