NR6A1 (Nuclear Receptor Subfamily 6 Group A member), also known as GCNF (Germ Cell Nuclear Factor), is an orphan member of the nuclear receptor gene superfamily. It has been shown to be expressed in the nervous system during development and during specific stages in maturing germ cells of the ovary and testis in the adult, and has probable roles in gametogenesis, neurogenesis, and normal embryonic development during gastrulation. Inactivation of GCNF in mouse results in abnormal posterior development, impaired midbrain development, insufficient closure of the neural tube, and eventual embryonic death. GCNF has been shown to be a repressor of OCT-4 and plays a critical role in the control of gene expression during embryogenesis and spermatogenesis. This antibody specifically reacts with the 55kd NR6A1 protein.