TET enzymes are successively expressed during human spermatogenesis and their expression level is pivotal for male fertility.

Study Question: Are ten-eleven-translocation (TET) 1-3 family enzymes involved in human spermatogenesis and do they impact male fertility?

Summary Answer: TET1, TET2 and TET3 are successively expressed at different stages of human spermatogenesis, and their expression levels associate with male fertility.

What Is Known Already: Spermatogenesis is a complex cell differentiation process accompanied by a drastic epigenetic remodeling. TET1-3 dioxygenases are essential for active DNA demethylation in the paternal pronucleus and in embryonic stem cells.