Branching and elongation activities of different Slit2 protein fragments. A, The total neurite length (left panel) or the branchpoint number (right panel) per neuron (mean ± SE;n > 33) is plotted against the concentration of different Slit2 protein fragments used in the E14.5 DRG culture. Slit2-N (▴), Slit2-C (●), and Slit2-U (▪). B, Slit2-U, but not Slit2-C, could block the activity of Slit2-N. The total neurite length or the branchpoint number is plotted against the concentration of either Slit2-U (■) or Slit2-C (○), which was added to the DRG culture stimulated by 400 ng/ml Slit2-N.