VASE exon expression alters NCAM‐mediated cell‐cell interactions

Publisher Website
Google Scholar
Abstract
The neural cell adhesion molecule (NCAM) is found on cells as several related polypeptides formed by alternative splicing of the single NCAM gene. The alternatively spliced 30‐bp VASE exon in the fourth immunoglobulin‐like domain is the structural variation nearest those portions of the polypeptide proposed to mediate cell‐cell adhesion. To test the ability of distinct forms of the NCAM molecules to mediate cell adhesion, L cells were transfected with expression vectors encoding rat 140 kD NCAM ± the VASE exon. L cell lines which expressed these polypeptides were isolated and tested for self‐aggregation in a low shear, rapid aggregation assay. Increased cellular aggregation of the transfectants was observed to be a function of the NCAM molecule expressed. These transfected cells showed segregation in a long term co‐aggregation assay: cells expressing NCAM — VASE formed aggregates which tended to exclude cells expressing NCAM + VASE and vice versa. These results provide direct evidence that this small difference in NCAM structure is sufficient to allow segregation of cells.