CDNA CLONING AND CHROMOSOMAL LOCALIZATION OF NEURAL ADHESION MOLECULENB-3 IN HUMAN

Neural adhesion molecules in the immunoglobulin superfamily play essen tial roles in axonal guidance during development, plasticity, and main tenance of synaptic connections in the adult brain, Recently, we repor ted two novel cDNAs encoding adhesion molecules, NB-2 and NB-3, in the contactin/F3 subgroup of the immunoglobulin superfamily from rat brai n, We have now isolated cDNA encoding human NB-3, The cDNA clone, hNB- 3, consists of 3,530 nucleotides with an open reading frame of 3,084 n ucleotides encoding 1,028 amino acids, It shares with rat NB-3 86% ide ntity in nucleotide sequences and 90% identity in amino acid sequences , Likewise, hNB3 exhibits 53% and 51% identity in nucleotide sequences and 43% and 44% identity in amino acid sequences with human contactin /F3 and human TAG-1/axonin-1, respectively, Northern blot analysis of mRNA isolated from different regions of the adult human nervous system showed that the hNB-3 mRNA content was regionally different by dozens -fold, although the mRNA was detected in all regions, as a transcript of 3.7 kb, The cerebellum showed the highest expression of hNB-3 mRNA among various regions of the nervous system, Chromosomal localization of hNB-3, using fluorescence in situ hybridization, was assigned to 3p 25-26., (C) 1998 Wiley-Liss, Inc.