FIG. 8.

Recovery of ligand binding function after addition of peptide linker. (A) Schematic diagram of the FNIII deletion series shown in Fig. 6, together with FN5L-AP containing a peptide linker (black triangle). Gray circles, IG domains; squares, FNIII domains. The black circles in PTPσ2-AP and PTPσ1-AP represent an additional 29-amino-acid segment (see the text). The binding pattern of each fusion protein is summarized as either nonbinding (white rectangle), strongly binding (black rectangle), or weakly binding (two gray shades) to BMs or muscle (Mu). (B) Amino acid sequence of Fnd5L-AP at the junction between FN5d (italic) and PLAP, with the added linker in boldface. (C to H) FN3d-AP (C and F), FN5d-AP (D and G), and FN5L-AP (E and H) RAP assays in E10 chicken embryo head sections, showing relative binding to muscle (C to E) or basement membrane ligands (F to H, arrows). Scale bar = 50 μm.