Northern blot and Western blot analysis of syndecan-4 expression in TF-1 and HEL cells. Northern blot analysis was performed using a digoxigenin-labeled hybridization probe for syndecan-4. A specific signal could be detected for syndecan-4 in TF-1 (A) and HEL (C) cells. GAPDH was used as a control (B and D). For Western blot analysis (E), HS proteoglycans from the supernatant of HEL cells were isolated and digested by heparinase/heparitinase (H) or chondroitinases AC/ABC (A) and submitted to SDS-PAGE on a 4% to 15% gel. The untreated sample is shown on lane N. Detection was performed using the syndecan-4 specific MoAb 8G3. The core protein of syndecan-4 is indicated by an arrowhead. It might be noted that in HEL cells a substantial amount of free core protein of syndecan-4 is detectable.