VASE exon expression alters NCAM-mediated cell-cell interactions.
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.
Chen
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Division of Basic Research, Children's Hospital Research Foundation, Cincinnati, Ohio 45229-2899.
Haines
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Maxson
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Akeson
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D000818:Animals; D002448:Cell Adhesion; D015816:Cell Adhesion Molecules, Neuronal / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002449:Cell Aggregation; D005091:Exons; D007739:L Cells; D051379:Mice; D017434:Protein Structure, Tertiary; D012326:RNA Splicing; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection
D015816:Cell Adhesion Molecules, Neuronal; D011993:Recombinant Fusion Proteins