Fig. 4. The specificities of polyclonal antibodies to Bb1C, Bb2C and ß-catenin. (A) Western blot analysis of S2 cells transiently transfected with plasmids for Bb1C-GFP (lanes 1, 4 and 7), Bb2C-GFP (lanes 2, 5 and 8) or no insert (lanes 3, 6 and 9). The same blot was repeatedly used for detection with polyclonal antibodies to GFP (lanes 1-3), Bb1C (lanes 4-6) and Bb2C (lanes 7-9). (B-D) Endodermal epithelium of an amphioxus stage N3 embryo double-stained with the anti-Bb2C (B) and anti-ß-catenin (C) antibodies. (D) The two images were colored and merged (B in purple and C in green). The signals yielded by the two antibodies were coincidently detected at the apical portions of the lateral cell surfaces as seen in white (arrowheads). En, endoderm; Ec, ectoderm. (E) Western blot analysis of amphioxus stage L1 larvae (18 hour) to indicate the specificity of the anti-ß-catenin antibody. Two bands of about 100 and 106 kDa were detected.