JMJD1B (jumonji domain containing 1B), also known as KDM3B, 5qNCA (5q Nuclear Co-Activator) or C5orf7, is a member of the JHDM2 histone demethylase family of proteins. Expressed in a wide variety of tissues, JMJD1B localizes to the nucleus and contains one JMJC domain and a C-terminal zinc finger motif. JMJD1B functions as a histone demethylase and, using iron as a cofactor, demethylates lysine-9 of Histone H3. This suggests that JMJD1B plays a central role in the histone code. The gene encod