OCT3, or Octamer-binding transcription factor 3, is a protein that plays a crucial role in regulating gene expression. It is part of the POU family of transcription factors and is involved in the development and maintenance of various tissues, particularly in the nervous system and embryonic stem cells. This protein binds to specific DNA sequences, influencing the transcription of target genes. OCT3 is essential for processes such as cell differentiation and stem cell pluripotency, making it a significant focus of research in developmental biology and regenerative medicine.