Repeating modular structure of the fibronectin gene: relationship to protein structure and subunit variation.

Analysis of the exon-intron structure of the rat fibronectin gene shows that exons correspond precisely with repeating structural units in the protein and that alternative use of some exons produces fibronectin subunits that differ by the presence or absence of certain structural modules. Secondary structure predictions suggest that the repeating structure of the protein is further subdivided into smaller structural units and that these also correspond with exons in the gene.