Polypeptide variation in an N-CAM extracellular immunoglobulin-like fold is developmentally regulated through alternative splicing.
The alternative splicing of a previously undiscovered 30 base exon confers a new level of polypeptide diversity on the N-CAM family of cell-surface glycoproteins. It results in the insertion of 10 amino acids into the fourth of five extracellular immunoglobulin-like folds. Each major size class of rat brain N-CAM mRNAs consists of members that contain or lack the exon. Furthermore, this splicing event is developmentally controlled: RNAs containing the inserted exon are expressed at extremely low levels (less than 3%) in embryonic brain but increase postnatally to 40%-45% of all N-CAM mRNAs in adult brain. Antibodies that recognize the alternative 10 amino acid segment react with a subset of N-CAM-expressing neurons in cultures of embryonic rat cells.
Small
S J
SJ
Division of Basic Research, Children's Hospital Research Foundation, Cincinnati, Ohio 45229.
Haines
S L
SL
Akeson
R A
RA
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000166:cytology / Q000378:metabolism; D015816:Cell Adhesion Molecules, Neuronal / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D055598:Chemical Phenomena; D002621:Chemistry; D000939:Epitopes / Q000276:immunology; D005091:Exons; D015870:Gene Expression; D007136:Immunoglobulins / Q000276:immunology; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis* / Q000276:immunology; D012326:RNA Splicing; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D051381:Rats
D000596:Amino Acids; D015816:Cell Adhesion Molecules, Neuronal; D000939:Epitopes; D007136:Immunoglobulins; D010455:Peptides; D012333:RNA, Messenger