Fig. 3

hFGF-2 production only detectable when promoter region and RBS are present. SDS-PAGE analysis of IPTG induced cells carrying the gene encoding hFGF-2 growing on LB medium (lanes 1–8) and glucose supplemented mineral salt medium DNB (lanes 10–15) collected 4 h after induction. Lane 1: N, T7⁺ RBS⁺ (non-induced control, total cell extract of cells containing the expression vector with promoter and with RBS in front of the hFGF-2 gene), lane 2: W, T7⁺ RBS⁺ (induced cells with promoter and with RBS), lanes 3, 12: W, T7⁺ ΔRBS (with promoter but without RBS), lanes 4, 13: W, ΔT7 RBS⁺ (without promoter but with RBS), lanes 5, 14: W, ΔT7 ΔRBS (without promoter and without RBS), lanes 6, 15: W, w/o plasmid (induced E. coli BL21(DE3) without expression vector), lanes 7, 10: S, T7⁺ RBS⁺ (soluble) and lanes 8, 11: I, T7⁺ RBS⁺ (insoluble cell fraction of induced cells containing the expression vector with promoter and with RBS). Lane 9: molecular mass marker, the position of hFGF-2 is indicated by an arrow. N: non-induced whole cell protein W: induced whole cell protein, S: induced soluble part, and I: induced insoluble part of whole cell protein