A novel gene, designated neurorep 1, was isolated by differential hybridization screening from a complementary DNA library constructed from the rat facial nucleus whose nerve had been transected seven days before sampling. In situ hybridization revealed that this gene was up-regulated in the repair stage after axotomy. The deduced protein, Neurorep 1, consists of 293 amino acid residues, and its molecular mass is approximately 34,000. Protein sequence motif search indicates that this protein has an ecto-5'-nucleotidase consensus sequence at the carboxyl terminal region. In vitro studies showed that Neurorep 1 significantly increased the activity of ecto-5'-nucleotidase, which is considered to be involved in regeneration and repair of the central nervous system. Neurorep 1 might play a significant role in the repair process of nerve tissues by its regulation of ecto-5'-nucleotidase activity.