The Human Recombinant GDNF and Study of Its Biological Activity.

The cDNA encoding the mature human glial cell derived neurotrophic factor(GDNF) was isolated by using RT-PCR method from total RNA extracted of fetal human brain. The expression plasmid pET-GDNF was constructed by inserting GDNF cDNA into plasmid pET-28a(+) containing T7 promoter and transformed into E.coli BL21(DE3). An expression strain BLGDNF was selected. SDS-PAGE analysis revealed that the human GDNF protein was highly expressed and accumulated up to above 30% of the total bacterial proteins in the form of inclusion body after the induction. The antibody to GDNF was prepared by immunization of rat using purified GDNF protein. Purified and refolded GDNF protein could significantly promote the survival of dopaminergic neurons.