OVERLAPPING AND DIFFERENTIAL EXPRESSION OF BIG-2, BIG-1, TAG-1, AND F3 - 4 MEMBERS OF AN AXON-ASSOCIATED CELL-ADHESION MOLECULE SUBGROUP OFTHE IMMUNOGLOBULIN SUPERFAMILY
Y. Yoshihara et al., OVERLAPPING AND DIFFERENTIAL EXPRESSION OF BIG-2, BIG-1, TAG-1, AND F3 - 4 MEMBERS OF AN AXON-ASSOCIATED CELL-ADHESION MOLECULE SUBGROUP OFTHE IMMUNOGLOBULIN SUPERFAMILY, Journal of neurobiology, 28(1), 1995, pp. 51-69
Axon-associated cell adhesion molecules (AxCAMs) play crucial roles in
the formation, maintenance, and plasticity of functional neuronal net
works. We report here a molecular cloning of a novel AxCAM, BIG-2. BIG
-2 is a member of TAG-1/F3 subgroup of the immunoglobulin (Ig) superfa
mily, with six Ig-like domains, four fibronectin type III-like repeats
, and a glycosyl phosphatidylinositol-anchoring domain. Recombinant BI
G-2 protein had a neurite outgrowth-promoting activity when used as a
substrate for neurons in vitro. To survey the spatial expression patte
rn of BIG-2 in comparison with other TAG-1/F3 subgroup members, an in
situ hybridization analysis was performed in adult and developing rat
brain sections with riboprobes specific for BIG-2, BIG-1, TAG-1, and F
3. The four AxCAM transcripts displayed cell type-specific expression
patterns with overlapping and distinct profiles. In adult hippocampus,
for example, we observed BIG-1 mRNA specifically in granule cells of
the dentate gyrus, BIG-2 mRNA highly in the CA1 pyramidal cells, TAG-1
mRNA predominantly in the CA3 pyramidal cells, and F3 mRNA in neurons
in all of these fields. These results suggest that BIG-2, BIG-1, TAG-
1, and F3 may play important roles in the formation and maintenance of
specific neuronal networks in the brain. (C) 1995 John Wiley & Sons,
Inc.