Intra- and extracellular concentrations of recombinant rhVEGF. Physcomitrella protoplasts were transiently transfected with pVSP-VEGF and pASP-VEGF in four (pVSP-VEGF and control) and seven (pASP-VEGF) independent transfections. After 5 days the concentrations of secreted and intracellularly retained recombinant protein were measured by ELISA. A: mean values of concentrations of extra- and intracellular rhVEGF measured by ELISA. B: Western blot with culture medium of transiently rhVEGF-producing cell. Control: untransfected moss protoplasts.