BHC80 is a component of BRAF-HDAC complex (BHC) involved in transcriptional repression of neuron-specific genes in non-neuronal cells. However, BHC80 is present in both neuronal and non-neuronal cells. To explore the physiological importance of BHC80 in vivo, and the precise mechanism underlying neuron-specific gene repression by BHC80, we have produced mutant mice lacking Bhc80. The loss of Bhc80 resulted in neonatal lethality without sucking mother's breast milk sufficiently. Although Bhc80-deficient mice showed no developmental defect in the neuronal and non-neuronal tissues, Bhc80 is indispensable for the survival of neonatal pups. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.