Acts as a transcriptional repressor for zinc finger transcription factors EGR1 and EGR2. Homomultimers may associate with EGR1 bound to DNA. Widely expressed in adult. In day 16 embryo highest levels in forebrain, thymus, salivary gland and cartilage. In day 16 embryo highest levels in forebrain, thymus, salivary gland and cartilage. The NAB conserved domain 1 (NCD1) interacts with EGR1 inhibitory domain and mediates multimerization. The NAB conserved domain 2 (NCD2) is necessary for transcriptional repression. Belongs to the NAB family.