Cloning and structural organization of the gene encoding the mouse glial cell line-derived neurotrophic factor, GDNF

cDNA for glial cell line-derived neurotrophic factor (GDNF) was cloned from mouse neonatal brain by the method of 5'-rapid amplification of cDNA end (5'-RACE), and the sequence of it's 5'-untranslated region (5'-UTR) was determined. The mouse GDNF gene was then isolated from a genomic library and analyzed for its nucleotide sequence. In vitro translation analysis indicated that the second ATG codon in an open reading frame is the translation start point. Structural analysis of the isolated clones showed that the GDNF gene was separated into three exons and the actual translation start point was present in the second exon. RNA blot hybridization analysis indicated that the GDNF mRNA is approximately 4.5 kb long. The transcriptional start site in the GDNF gene was determined and a typical TATA box sequence was found in the promoter region. On the other hand, the gene expression of GDNF in C6 glioma cells was transiently induced by treatment with phorbol myristate acetate (PMA), but not by forskolin.