cDNA cloning strategy. The upper panel schematically illustrates the lg domain structure of chicken BEN and goldfish neurolin. The five extracellular V-type and C-type lg domains and transmembrane domain (TM) are shown. The amino-terminal sequences of rat F84.1 and KG-CAM (experimentally determined) and the deduced N-terminal sequence of chicken BEN are shown. The region of cytoplasmic sequence identity between chicken BEN and goldfish neurolin is shown at right. These amino acid sequences were used variously to derive the degenerate oligonucleotide primers HCA51, HCA52, and HCA31 shown below.