The present invention concerns methods and compositions for producing a neublastin polypeptide as well as local delivery of neublastin to specific regions of the nervous system including the central nervous system for example by gene therapy. The biologically active neublastin polypeptide is produced from a construct not encoding naturally occurring neublastin pro-region, i.e. a construct comprising a nucleic acid with a promoter sequence operably linked to a nucleotide sequence encoding a signal peptide and a neublastin polypeptide, wherein said nucleotide sequence does not encode a neublastin pro-region.
