Using a polymerase chain reaction-mediated cloning procedure, we have identified a novel member, termed ANA (from Abundant in Neuroepithelium Area), of Tob/BTG1 family of antiproliferative genes. Molecular cloning and analysis of cDNAs revealed that the human and mouse ANA encoded a protein of 252 amino acids. The amino-terminal half of ANA was homologous to the previously characterized antiproliferative gene products, BTG1, PC3/TIS21/BTG2, and Tob. The human ANA gene was localized at chromosome 21q11.2-q21.1. ANA was expressed in a variety of tissues and cell lines, its expression being high in the ovary, testis, prostate, thymus, and lung. Further analysis revealed that ANA expression was high in the ventricular zone of the developing central nervous system. Finally, overexpression of ANA impaired serum-induced cell cycle progression from the G0/G1 to S phase. In conclusion, ANA is a fourth member of the Tob/BTG1 family that might play roles in neurogenesis in the central nervous system.