Fig. 1. CS-A, but not CS-C, repels axons in a 4-sulfation-dependent manner. (A-F) Axonal guidance spot assays were performed with (A) chicken CSPG, (B) chicken CSPG treated with cABC, (C) CS-A, (D) CS-A partially digested with cABC, (E) CS-C, (F) CS-A treated with chondro-4-sulfatase. Each test substance was immobilized onto a PLL-coated coverslip and the behavior of axons at the interface between PLL and the sample (red) was quantified as described in the Materials and Methods. (G) Quantitative analysis of axonal behavior at the interface. Data are expressed as the mean ± s.d. Scale bar: 25 µm.