Figure 2

Ciona intestinalis tenascin. A. The amino acid sequence of a tenascin from C. intestinalis. The N-terminal linker region is at the top, with a signal peptide shown in bold and putative heptad repeats underlined. Between amino acids 208 and 458 are 8 EGF-like repeats. These are followed by 18 FN type III domains between amino acids 459 and 2120. The tryptophan (w), leucine (l) and tyrosine (y) residues that are characteristic of these domains are highlighted and aligned, and a putative integrin-binding motif (rge) found in the third FN type III domain is shown in bold. The C-terminal FReD is composed of amino acids 2128 through 2355. B. The repeat and domain organization of the C. intestinalis tenascin shown in A. A key to the shapes symbolizing each domain can be found in the legend to Figure 1. C. A rabbit antiserum against a recombinant fragment of C. intestinalis tenascin was used to immunostain whole larvae. The antiserum recognized the tunic, a line of matrix in the tail (arrows), and faintly labelled the tail muscles (between the arrows). D. The rabbit preimmune serum inconsistently labelled the tunic but not the line of matrix in tail or the tail muscles.