This gene belongs to the RING finger family, members of which encode proteins characterized by a RING domain, a;zinc-binding motif related to the zinc finger domain. The gene product can bind DNA and can act as a transcriptional;repressor. It is associated with the multimeric polycomb group protein complex. The gene product interacts with the;polycomb group proteins BMI1, EDR1, and CBX4, and colocalizes with these proteins in large nuclear domains. It;interacts with the CBX4 protein via its glycine-rich C-terminal domain. The gene maps to the HLA class II region,;where it is contiguous with the RING finger genes FABGL and HKE4.