The cDNA that encodes full-length human plasminogen (Glu(1)-hPg) has been e
xpressed in Drosophila Schneider S2 cells under the influence of the Drosop
hila BiP protein signal sequence, which allowed the protein to be secreted
into the medium. A procedure was devised for clonal selection of high-expre
ssing cells, which were then used for large-scale expression of 10-15 mg/li
ter of the protein in the culture medium. The protein produced using this s
ystem was extensively characterized and contained full-length recombinant (
r) Glu(1)-hPg plasminogen. As with human plasma Glul-hPg, the SE-expressed
protein underwent the Cl--induced transition to the tight conformation, whi
ch resulted in a weakly activatable zymogen. The addition of the ligand, E-
amino caproic acid, induced the relaxed conformation of r-Glu(1)-hPg, which
was highly activatable, again in agreement with similar data for human pla
sma Glu(1)-hPg. The thermal stability of the S2-expressed r-Glu(1)-hPg also
correlated well with that of human plasma hPg, These studies show that int
act r-Glu(1)-hPg can be produced in high yield in Drosophila Schneider S2 c
ells, which possesses similar properties to its human plasma counterpart. (
C) 1999 Academic Press.