Fig. 2. Characterisation of PSA glycoproteins in goldfish and zebrafish brain. Western blots were reacted with antibodies against PSA or against NCAM. (A-C) Proteins from goldfish brain membranes immunoprecipitated with mAb 735 against PSA. They consist of a broad high molecular weight smear between 120 and 240 kDa when reacted with mAb 735 (A). After endo N treatment, discrete bands are visible at 120 kDa and 170 kDa in a protein stain (B). The band at 170 kDa is also recognised by mAb D3 against the intracellular domain of chick NCAM (C). (D-G) Immunoblots of zebrafish brain membranes reacted with mAb 735 (D,E), a polyclonal serum against goldfish proteins immunoprecipitated with mAb 735 (F) and mAb D3 (G). mAb 735 recognised a broad band between 120 and 240 kDa (D). This labeling was completely abolished when the membranes were treated with endo N before electrophoresis (E). The polyclonal serum recognised three major bands at 170 kDa, 140 kDa and 120 kDa (F), a pattern typical of NCAM in higher vertebrates. mAb D3 recognised a band at 170 kDa (G).